## Summary
Buffer-side data layer used by the rest of the mollifier phase-3 stack.
- `buffer.ts` gains entry inspection (`getEntry`), idempotency lookup
(`lookupIdempotency`), in-place snapshot mutation (`mutateSnapshot`),
and dwell tracking. All atomic via Lua.
- `mollifierSnapshot.server.ts`: shared `MollifierSnapshot` type plus
(de)serialise helpers.
- Drops the entry-TTL config and its env var. The drainer is the
recovery mechanism; an entry that survives the drainer should surface as
a stale-sweep alert, not silently TTL away.
Adds methods to the buffer interface; nothing consumes them yet.
Subsequent PRs in the stack wire trigger-time mollify, read-fallback,
and mutation paths against this surface.
## Test plan
- [x] \`pnpm run typecheck --filter webapp\` passes
- [x] \`pnpm run test --filter @trigger.dev/redis-worker
packages/redis-worker/src/mollifier/buffer.test.ts\` passes
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Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Daniel Sutton
3924aa4adb