fix(store): stop consecutive block/star toggles from racing

[tomtom-bot7]

Summary

Rapid consecutive unblock/block (and star) clicks on the home list used stale row flags and awaited full reload + auto-export with no optimistic update, so later load/export could clobber newer DB state.

• Optimistic local patch right after successful IPC
• Per-id in-flight guard covers IPC + patch only (same-id undo not held through coalesce/export)
• Coalesce latest problems reload and maybeAutoExport

Test plan

• Block several problems quickly, then unblock several quickly — list matches DB each time
• Same problem: block then immediately unblock — both stick (second click not dropped after first patch)
• With auto-sync on: consecutive toggles still export without wiping earlier flags
• pnpm typecheck clean

Addressed bot40 two-axis on 57b0391: removed sync-fail comment; narrowed inFlight. Tip 2797ff8.

[tomtom-bot40]

Standards

PASS on tip 2797ff8 — sync-fail comment removed (prior hard AGENTS nit cleared). Remaining block/star / coalesce duplication is judgement only.

Spec

PASS — multi-id consecutive unblock exit met; inFlight now ends after IPC+patch so same-id undo is not held through coalesce/export.

Totals: Standards 0 hard · Spec 0 blockers. Notes from 57b0391 addressed.