discussion(desktop): v2 usage IPC query surface is unreachable (6 orphan channels of 191 handlers) #3214

Found by a repo-wide simplification audit; re-verified with git grep -aI.

The v2 usage query surface is unreachable from the shipped app:

• apps/desktop/src/main/runtime-host-usage-ipc-main.ts registers six channels (usage:summary, usage:buckets, usage:logs, usage:pricing:list|put|reset) and they are the only 6 of the app's 191 IPC handlers with zero preload exposure and zero renderer callers.
• usage:pricing:changed is the only main-process send() in the whole app with no listener.
• The shipped Usage settings page uses the v1 path instead: settings-store scan-aggregation via runtime-host-boot.ts → usage-settings-page.tsx.

Related architecture context: usage metering is currently double-written (recordLlmCall legacy writer vs recordModelCallAttempt canonical, merged at query time by usage-ledger-merge), with Host auxiliary calls (memory extraction, Daily Review, title/recap) still on the legacy writer.

Question (go/stop): is the orphan IPC surface the half-landed renderer side of a new Usage page (if so — progress check), or should the v2 query surface be removed until a consumer exists? Deciding which ledger is the long-term authority for auxiliary Host calls is a separate architecture decision this issue only flags.