refactor(reports): split LETTER_SUBJECT_FONT_SIZE from SUBHEADER_FONT_SIZE (#1953)

.claude/agent-memory/product-architect/MEMORY.md

@@ -2,7 +2,7 @@
 
 ## Topic Files
 
-- [Recurring patterns & traps](recurring-patterns.md) — polymorphic FK cleanup, XOR CHECK vs SET NULL, forked-function drift, test smells, cross-layer contract drift, ajv `anyOf`, N+1 sites, async writes surviving state resets, the revert test for fixes that only relax an invariant — re-run it yourself on round 2 (#1968/PR #2002), cross-reference rot in documented-bound comments (#1939), usePreferences per-instance store + serialized-write-queue review (#1955), capability-retained-but-producer-removed (#1959), reinstated-producer-vs-negative-guards (#1965), AC reversal by a polish issue (#1959), amount-threshold booleans narrowing status-existence booleans (#1897), prettier is not CI-gated, single-occurrence delimiter guard tests + German ordinals vs list markers + pre-validating regex fix specs (#1952), `Pick<>` is not a forcing function + caller-supplied monotonic seq reintroduces the ref + cascade tables smuggle behaviour changes + neutralised-trigger-left-in-code (#1947), tier factory only forces the cases that spread it (#1988), regex mirroring a third-party grammar + `parseInt` trailing garbage + env vars documented in four places (#1970, PR #1989), guard-deleted-because-it-looked-like-the-bug + rate-limit identity-check gate + `request.ip` nullability types-lie + CVE test needs a negative control (#1995, PR #1998), prettier config resolution is path-based so /tmp baseline checks lie + wiki is not prettier-ignored + document the invariant not the absence-of-code (#1998 wiki pass), comment-refreshed-but-assertion-left-behind + contract inversion makes pre-existing negatives unconditional + surgical tagging misses read-only value nodes (#1910, PR #2004 r2), the-prop-landed-is-not-the-prop-is-wired + redundant-tag-a-test-asserts + `aria-label` cannot be language-tagged (#1910, PR #2004 r3), `count >= 1` + all-match is a per-instance assertion masquerading as coverage — revert each call site individually, use `toBe(N)` (#1910, PR #2004 r4), untyped E2E route fixtures drift from shared contracts + consumer early-return masks an incomplete fixture + duplicate Playwright route globs are an ordering dependency (#2005, PR #2006), widen-then-`as`-narrow defeats union exhaustiveness + a hardening PR falsifies its own ADR in four predictable places + key-echo fixtures are non-discriminating (#2001, PR #2007), a revert test can prove a _different_ proposition than the one it licenses + implementing a documented rule for the first time is when you learn the rule is wrong + three forked `collectAllStrings` copies (#2003, PR #2008), **a spec's own "purely additive, no E2E changes needed" claim is the tell that existing tests encoded the OLD derivation — a derivation change is never purely additive** + re-seeding a fixture without re-deriving its arithmetic expectation + `toContainText('<amount> (label)')` breaks the moment a badge is rendered between them, so assert the note locator not sibling-node adjacency (#1911, PR #2015), **the two-command env-var drift sweep (`getValue(` read-set vs `^| \`VAR\`` doc-set, then grep the enablement sentences separately — a stated variable *count* is a second drift surface the name diff cannot see) + wiki tables are char-width-padded so measure with python `len()` not `awk length()` (em-dashes are 3 bytes) + two open findings: the `BACKUP_DIR` default/gate is wrong on Architecture.md and API-Contract.md's `splitKind` table is a latent `format:check` failure (#1992, wiki `e14bcbe`)**, **operator-facing prose is a behavioural claim a validator must back — hyperlinking `vercel/ms` while enforcing a regex subset, a caution box falsified by `parseInt` leniency, and `trustProxy: 1` being a hop count not "trust all proxies" (#1990, PR #2027)**, **fuzz the verbatim ports when a doc comment carries an induction proof (a hand-trace only re-reads the author's argument) + a safety argument phrased as a *ratio* is falsified by any clamp in the chain (#1940, PR #2032)**, **flex `gap` + child `margin` are additive not collapsing (bit twice in one PR — code AND the spec reviewing it) + a cohesive prop group modelled as N independent optionals + "leaves N chars for X" comments invite a guard test that pins a fiction: check whether X is bounded at all and whether the consumer clips or paginates (#1941, PR #2033)**
+- [Recurring patterns & traps](recurring-patterns.md) — polymorphic FK cleanup, XOR CHECK vs SET NULL, forked-function drift, test smells, cross-layer contract drift, ajv `anyOf`, N+1 sites, async writes surviving state resets, the revert test for fixes that only relax an invariant — re-run it yourself on round 2 (#1968/PR #2002), cross-reference rot in documented-bound comments (#1939), usePreferences per-instance store + serialized-write-queue review (#1955), capability-retained-but-producer-removed (#1959), reinstated-producer-vs-negative-guards (#1965), AC reversal by a polish issue (#1959), amount-threshold booleans narrowing status-existence booleans (#1897), prettier is not CI-gated, single-occurrence delimiter guard tests + German ordinals vs list markers + pre-validating regex fix specs (#1952), `Pick<>` is not a forcing function + caller-supplied monotonic seq reintroduces the ref + cascade tables smuggle behaviour changes + neutralised-trigger-left-in-code (#1947), tier factory only forces the cases that spread it (#1988), regex mirroring a third-party grammar + `parseInt` trailing garbage + env vars documented in four places (#1970, PR #1989), guard-deleted-because-it-looked-like-the-bug + rate-limit identity-check gate + `request.ip` nullability types-lie + CVE test needs a negative control (#1995, PR #1998), prettier config resolution is path-based so /tmp baseline checks lie + wiki is not prettier-ignored + document the invariant not the absence-of-code (#1998 wiki pass), comment-refreshed-but-assertion-left-behind + contract inversion makes pre-existing negatives unconditional + surgical tagging misses read-only value nodes (#1910, PR #2004 r2), the-prop-landed-is-not-the-prop-is-wired + redundant-tag-a-test-asserts + `aria-label` cannot be language-tagged (#1910, PR #2004 r3), `count >= 1` + all-match is a per-instance assertion masquerading as coverage — revert each call site individually, use `toBe(N)` (#1910, PR #2004 r4), untyped E2E route fixtures drift from shared contracts + consumer early-return masks an incomplete fixture + duplicate Playwright route globs are an ordering dependency (#2005, PR #2006), widen-then-`as`-narrow defeats union exhaustiveness + a hardening PR falsifies its own ADR in four predictable places + key-echo fixtures are non-discriminating (#2001, PR #2007), a revert test can prove a _different_ proposition than the one it licenses + implementing a documented rule for the first time is when you learn the rule is wrong + three forked `collectAllStrings` copies (#2003, PR #2008), **a spec's own "purely additive, no E2E changes needed" claim is the tell that existing tests encoded the OLD derivation — a derivation change is never purely additive** + re-seeding a fixture without re-deriving its arithmetic expectation + `toContainText('<amount> (label)')` breaks the moment a badge is rendered between them, so assert the note locator not sibling-node adjacency (#1911, PR #2015), **the two-command env-var drift sweep (`getValue(` read-set vs `^| \`VAR\`` doc-set, then grep the enablement sentences separately — a stated variable *count* is a second drift surface the name diff cannot see) + wiki tables are char-width-padded so measure with python `len()` not `awk length()` (em-dashes are 3 bytes) + two open findings: the `BACKUP_DIR` default/gate is wrong on Architecture.md and API-Contract.md's `splitKind` table is a latent `format:check` failure (#1992, wiki `e14bcbe`)**, **operator-facing prose is a behavioural claim a validator must back — hyperlinking `vercel/ms` while enforcing a regex subset, a caution box falsified by `parseInt` leniency, and `trustProxy: 1` being a hop count not "trust all proxies" (#1990, PR #2027)**, **fuzz the verbatim ports when a doc comment carries an induction proof (a hand-trace only re-reads the author's argument) + a safety argument phrased as a *ratio* is falsified by any clamp in the chain (#1940, PR #2032)**, **flex `gap` + child `margin` are additive not collapsing (bit twice in one PR — code AND the spec reviewing it) + a cohesive prop group modelled as N independent optionals + "leaves N chars for X" comments invite a guard test that pins a fiction: check whether X is bounded at all and whether the consumer clips or paginates (#1941, PR #2033)**, **a mutation count is not evidence of independent coverage — diff a new test's assertion body against its neighbours before trusting its title, esp. a negative-dependency title whose body never names the dependency + when a structural guard would have to re-encode the coupling under removal, a reason-carrying comment IS the right tool (#1953, PR #2035)**
 - [Dual-rail aggregation](dual-rail-aggregation.md) — Rail A/B tagged-deposit invariants (#1891/PR #1894), residual-denominator rule, isSplit UNION
 - [Source-report split inference](source-report-split-inference.md) — budgetLines[]/deposits[] are this-source-scoped so array-shape gates are proxies; **`splitKind` SHIPPED #1911/PR #2015** incl. the ≠S-per-arm predicate, the residual arithmetic proving `(less deposit)` in both directions, the UNION-dedup/`COUNT(*)` trap, and why `isSplit` must be retained as an independent cross-check; pdfmake `'2*'` width trap; wiki + shared type JSDoc fixed (#1914, #1917/PR #1994)
 - [Story reviews](story-reviews.md) — per-story and per-PR review log

.claude/agent-memory/product-architect/recurring-patterns.md

@@ -1543,3 +1543,42 @@ row on its own — and it is the one that fails loudly if the Usage column ever
 and whether the consumer clips or paginates. Routed to #1950 (chunk-ceiling drift guard) rather than a
 bespoke test; needs `USAGE_TEXT_MAX_LENGTH` exported. Keep the constant in the editor — an input
 constraint living in the renderer inverts the dependency.
+
+## A duplicate test with a stronger title, and when a comment beats machinery (#1953, PR #2035)
+
+Two findings from reviewing the split of `LETTER_SUBJECT_FONT_SIZE` out of `SUBHEADER_FONT_SIZE` in
+`client/src/lib/reportPdf/pageGeometry.ts`. The split itself was clean (own literal `12`, not an alias;
+`headerFootprint()`/`PAGE_TOP_MARGIN` byte-identical; reason-carrying comment; inverted comment removed).
+
+**(a) A new test whose assertions duplicate an existing test, under a title that claims more.**
+`pageGeometry.test.ts:98-101` was assertion-for-assertion identical to the pre-existing test at lines
+160-167 (`toBe(93)` + `toBe(Math.ceil(headerFootprint() + 15))`, order swapped) but titled *"PAGE_TOP_MARGIN
+does not depend on letterSubject.fontSize"* — a proposition its body never references. Zero added
+discrimination; it catches exactly the older test's mutation set.
+
+**Why:** QA's mutation evidence *corroborated* rather than exposed it — "SUBHEADER 12→11 fails 4 tests"
+reads as strong coverage, but two of the four are the duplicated pair. **A mutation count is not evidence
+of independent coverage; it counts assertions, not propositions.** Compare each new test's failing-mutation
+set against the existing suite's, not against zero. Same family as the PR #2008 "revert test proves a
+different proposition than the one it licenses" and the PR #2004 r4 `count >= 1` finding.
+**How to apply:** when a new test lands next to an existing one in the same file, diff the assertion bodies
+before reading the titles. A title asserting a *negative dependency* ("X does not depend on Y") whose body
+never mentions Y is the tell.
+
+**(b) When a comment is genuinely the right guard — the argument, not the shrug.**
+Two adjacent `expect(...).toBe(12)` assertions protected only by a "do NOT deduplicate these" comment is
+the right shape here. Not because no machinery exists, but because: (1) what is guarded is a *test's own
+discrimination* — collapsing it loses coverage, it does not regress production, since the production split
+and its comment stand regardless; and (2) **any structural guard would have to encode the coupling you just
+removed** — "these two `number`s must be permitted to differ" is not expressible in TS, and its closest
+approximation is exactly what already exists: two identifiers, two literals. The production split *is* the
+structural guard.
+
+Rejected strengthenings, both costing more than the comment: asserting the constant through its role in
+`headerFootprint()` restates production's formula in the test (the very anti-pattern `pageGeometry.ts`'s
+own header comment warns against, from #1929); mirroring the `TABLE_SMALL_FONT_SIZE` constant-to-style tie
+needs a module-private constant exported purely to be read by a test.
+**How to apply:** before proposing machinery for a test-integrity concern, ask what the failure mode
+actually costs (coverage loss vs regression) and whether the enforcement would re-express the coupling
+under removal. If both answers are "yes", a comment naming the *reason* is the correct tool — and say so
+affirmatively rather than as an absence of alternatives.

.claude/agent-memory/qa-integration-tester/MEMORY.md

@@ -15,6 +15,7 @@
 
 ## Recent bug/story notes (2026-08)
 
+- [Issue #1953 — independent-pinning test hygiene](story-1953-independent-pinning.md) (2026-08-06, PR #2035) — a duplicate assertion inflated a mutation-failure count without adding discrimination; a test title claimed an independence guarantee ("X does not depend on Y") that no assertion in its body actually tested — dedupe against the *pre-existing* suite, not just new tests, and re-check names against bodies only.
 - [Issue #1941 — EditableField maxLength](story-1941-editable-field-maxlength.md) (2026-08-06) — jsdom does NOT clamp controlled-input value/fireEvent.change against `maxlength` attr (verified empirically); a broken #1932 DOM-shape test was RIGHT — it caught a real additive flex-gap+margin spacing regression, don't reflexively "fix" a test a new wrapper breaks; ariaDescribedBy has exactly 4 reachable id-count combos (0/1/2/3, fixed order).
 - [Issue #1940 — continuation marker + runt-merge](story-1940-continuation-marker-runt-merge.md) (2026-08-06) — `packUsageCellRowsWithMinimum`/`… ` marker; centralized `stripContinuationMarker` pattern (both test files); ripple far wider than the 2 named tests (whole "cell-scope invariant" block's shared helper in realRender.test.ts); fontkit glyph-id-0 technique (added as pinned devDependency); blank pdfmake cells DO get `.positions`; mid-list-runt fixture recipe; git-revert genuine-regression proof (clean import-error + 2 real assertion failures).
 - [Issue #1912 — ESM mock blast radius](issue-1912-esm-mock-blast-radius.md) (2026-08-06) — new export on a shared module breaks a *different* file's partial `jest.unstable_mockModule` factory, not the one I checked; mechanical sweep + batch-jest-run pattern

.claude/agent-memory/qa-integration-tester/story-1953-independent-pinning.md

@@ -0,0 +1,47 @@
+---
+name: story-1953-independent-pinning
+description: Issue #1953 (LETTER_SUBJECT_FONT_SIZE/SUBHEADER_FONT_SIZE split) — mutation-count pitfall and test-title overclaim caught in PR #2035 review
+metadata:
+  type: feedback
+---
+
+Writing regression coverage for `client/src/lib/reportPdf/pageGeometry.test.ts` (two module-private
+constants, `LETTER_SUBJECT_FONT_SIZE`/`SUBHEADER_FONT_SIZE`, deliberately split apart with equal
+literals). Wrote 3 new tests: pin `PDF_STYLES.letterSubject.fontSize`, pin
+`PDF_STYLES.subheader.fontSize`, and a third asserting `PAGE_TOP_MARGIN`/`headerFootprint()`. Ran the
+standard backup/restore mutation technique ([[story-1929-round2-real-render-technique]]) both
+directions and reported "confirmed discriminating" because the SUBHEADER_FONT_SIZE 12->11 mutation
+failed 4 tests, not 1.
+
+`product-architect` caught what the mutation count masked, in PR #2035 review: the third test was
+**assertion-for-assertion identical** to a pre-existing test 60 lines below (same two `toBe` checks,
+order swapped) — zero added discrimination. The 4-failure count was itself the tell in hindsight: it
+included *both* copies of the duplicated pair failing for the identical reason, not four independent
+reasons. A mutation count only proves "this mutation moves some needle" — it does not prove each
+individual failing assertion is pulling separate weight. Check for duplicate assertions against the
+*existing* suite before citing a multi-test-failure count as evidence of thoroughness.
+
+Second, sharper problem: the test's title claimed *"PAGE_TOP_MARGIN does not depend on
+letterSubject.fontSize"* while **neither assertion in the body referenced `letterSubject`** — the
+title asserted a causal-independence guarantee (issue's own Verification section: "change the
+subject size and no page reflows") that the body never tested, because neither constant is exported
+so a live-mutation-based standing assertion isn't expressible in the permanent suite. **A test name
+that licenses a stronger claim than its body establishes is worse than no test** — a future reader
+trusts the name, concludes the guarantee is covered, and stops looking.
+
+Resolution: deleted the duplicate test outright (architect's stated preference over retitling, since
+the pre-existing test already covers the formula and duplication is its own maintenance cost) and
+left an explanatory comment at the deletion site documenting: why it was removed, that the "no page
+reflows" guarantee was only proven by the one-off manual mutation test (not a standing assertion),
+and what would make it expressible in code if that changes later (an exported computation helper).
+
+**Why**: mirrors [[bug-1955-echo-race-harness]]'s mutation-probe discipline but adds a check that
+discipline didn't include — dedupe candidate assertions against the pre-existing suite, not just
+against the new tests in the same PR, before trusting a failure count.
+
+**How to apply**: whenever citing "N assertions failed under this mutation" as proof of
+discrimination, first check none of those N are a near-identical restatement of a pre-existing test
+elsewhere in the file (same expected values, same formula, reordered). And before naming a test,
+re-read the name against only the assertion body — if the name asserts an independence/causality
+claim ("X does not depend on Y") but no assertion in the body actually varies or references Y, either
+write an assertion that does or narrow the name to what's actually checked.