Repo hygiene: remove scratch artifacts, consolidate docs, and dedupe useRecentLedgers

.gitignore

@@ -42,3 +42,6 @@ test-results/
 playwright-report/
 blob-report/
 playwright/.cache/
+
+# Storybook
+storybook-static/

docs/README.md

@@ -0,0 +1,26 @@
+# Documentation Index
+
+This directory holds the current, canonical documentation for the project.
+Each topic has exactly one current document. If you are looking for a topic
+that used to live at the repository root, it has been consolidated here.
+
+## Topics
+
+| Topic | Document |
+| --- | --- |
+| Testing strategy and how to run tests | [TESTING.md](./TESTING.md) |
+| Transaction history (feature, design, and implementation) | [TRANSACTION_HISTORY.md](./TRANSACTION_HISTORY.md) |
+| Performance notes | [PERFORMANCE.md](./PERFORMANCE.md) |
+
+## Archive
+
+Documents that described work already merged, or that have been superseded by
+the consolidated documents above, live under [`archive/`](./archive/). They are
+kept for historical reference only and are **not** current.
+
+- `archive/SIMULATION_IMPLEMENTATION_CHECKLIST.md`
+- `archive/REACT_QUERY_RECENT_LEDGERS.md`
+- `archive/TRANSACTION_HISTORY_DELIVERY.md`
+- `archive/TRANSACTION_HISTORY_DOCUMENTATION.md`
+- `archive/TRANSACTION_HISTORY_IMPLEMENTATION.md`
+- `archive/TESTING_STRATEGY.md`

docs/TESTING.md

@@ -0,0 +1,64 @@
+# Testing
+
+This is the single current testing document for the project. It replaces the
+former root-level `TESTING.md` and `TESTING_STRATEGY.md`, which described the
+same testing approach in two overlapping files.
+
+## Goals
+
+- Catch regressions before they reach `main`.
+- Keep tests fast enough to run on every change.
+- Cover the critical paths: ledger ingestion, transaction history, and the
+  simulation flow.
+
+## Test layers
+
+### Unit tests
+
+Small, fast, and isolated. They cover pure logic such as formatting helpers,
+parsers, and reducers. Prefer these whenever the behavior can be exercised
+without a network or a database.
+
+### Integration tests
+
+Exercise modules together against a test database or mocked services. Use these
+for data access, query hooks, and anything that crosses a module boundary.
+
+### End-to-end tests
+
+Drive the application the way a user would. Keep the suite small and focused on
+flows that must never break, such as loading recent ledgers and viewing a
+transaction's history.
+
+## Running the tests
+
+```sh
+# all tests
+npm test
+
+# a single file
+npm test -- path/to/file.test.ts
+
+# watch mode during development
+npm test -- --watch
+```
+
+## Conventions
+
+- Place tests next to the code they cover, using the `*.test.ts` suffix.
+- Name tests after the behavior under test, not the implementation.
+- Avoid snapshot tests for anything that changes often.
+- Mock external services at the boundary; do not reach into their internals.
+- Keep each test independent — no shared mutable state between cases.
+
+## What to test
+
+- New behavior: add a test that fails without the change.
+- Bug fixes: add a regression test that reproduces the original bug.
+- Refactors: rely on existing tests; add coverage only for newly exposed paths.
+
+## Continuous integration
+
+The full suite runs on every pull request. A change is not ready to merge until
+the suite passes. Flaky tests should be fixed or removed rather than retried
+indefinitely.

docs/TRANSACTION_HISTORY.md

@@ -0,0 +1,40 @@
+# Transaction History
+
+This is the single current document describing the transaction-history feature.
+It consolidates the former root-level `TRANSACTION_HISTORY_DELIVERY.md`,
+`TRANSACTION_HISTORY_DOCUMENTATION.md`, and
+`TRANSACTION_HISTORY_IMPLEMENTATION.md`, which are now superseded.
+
+## Overview
+
+The transaction-history feature lets a user browse the transactions associated
+with their account. It is backed by the recent-ledgers data layer and rendered
+through the transaction-history UI.
+
+## Data layer
+
+- Recent ledgers are fetched with the `useRecentLedgers` hook, which wraps the
+  React Query cache and exposes loading, error, and data states to consumers.
+- The hook is the single source of truth for ledger data; UI components should
+  consume it rather than fetching ledgers directly.
+- Query keys and cache invalidation live alongside the hook so that refetches
+  stay consistent across the app.
+
+## UI
+
+- The transaction-history view renders the ledgers returned by
+  `useRecentLedgers`, handling the loading and empty states.
+- Each entry links to its transaction detail where applicable.
+
+## Delivery notes
+
+The feature has been merged. The per-delivery documents that tracked its
+implementation (`TRANSACTION_HISTORY_DELIVERY.md`,
+`TRANSACTION_HISTORY_DOCUMENTATION.md`,
+`TRANSACTION_HISTORY_IMPLEMENTATION.md`) have been consolidated into this file
+and removed from the repository root.
+
+## See also
+
+- [Documentation index](./README.md)
+- [Testing](./TESTING.md)

src/hooks/useRecentLedgers.ts

@@ -30,6 +30,11 @@ export interface UseRecentLedgersResult {
  * Recent Stellar ledgers for `network`, cached and deduplicated by React
  * Query instead of the previous `useEffect` + local `useState` fetch.
  *
+ * This is the single canonical implementation of `useRecentLedgers` for the
+ * app. The former duplicate under `app/hooks/useRecentLedgers.ts` has been
+ * removed (see #585); every importer must resolve to this module so caching,
+ * polling, and error behaviour stay consistent across the codebase.
+ *
  * `refresh()` is a `useMutation`, not a plain `refetch()` call, specifically
  * to get optimistic-update semantics: clicking refresh flips `isRefreshing`
  * true synchronously (before the network round-trip resolves) so the UI can