v1.33.0.0 docs: design doc, P2 perf TODOs, gbrain guidance block, changelog

docs/designs/SYNC_GBRAIN_BATCH_INGEST.md: full design doc with the 8
decisions (D1-D8), source-verified gbrain behaviors (content_hash
idempotency, frontmatter parity, path-authoritative slug, per-file
failure surface), measured performance vs plan target, F9 hash
migration one-time cliff note, and follow-up TODOs.

CLAUDE.md: append `## GBrain Search Guidance` block from /sync-gbrain
indicating this worktree's pin and how the agent should prefer gbrain
search over Grep for semantic queries.

TODOS.md: P2 `gbrain import` perf-on-large-staging-dirs investigation
(5,131 files takes >10min in gbrain when 501 takes 10s — likely N+1
SQL or auto-link reconciliation). P3 cache-no-changes-since-last-import
at the prepare-batch level for true no-op fast paths.

VERSION + package.json: bump to 1.33.0.0 (queue-aware via
bin/gstack-next-version — skipped v1.32.0.0 which is claimed by
sibling worktree garrytan/wellington / PR #1431).

CHANGELOG.md: v1.33.0.0 entry per the release-summary format.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

package.json

@@ -1,6 +1,6 @@
 {
   "name": "gstack",
-  "version": "1.31.0.0",
+  "version": "1.33.0.0",
   "description": "Garry's Stack — Claude Code skills + fast headless browser. One repo, one install, entire AI engineering workflow.",
   "license": "MIT",
   "type": "module",