fix(gbrain-sync): --full produces an empty code index on first run of a new repo

[jetsetterfl]

Problem

The first /sync-gbrain --full on a new repo produces a code index with 0 pages while the stage reports OK. Semantic code search (gbrain code-def / code-refs / search) then silently returns nothing for that repo.

gstack-gbrain-sync.ts:runCodeImport selects the code-stage command by mode:

const syncArgs = args.mode === "full"
  ? ["reindex-code", "--source", sourceId, "--yes"]      // re-embeds EXISTING pages
  : ["sync", "--strategy", "code", "--source", sourceId]; // the walk that CREATES pages

gbrain reindex-code only re-embeds pages that already exist; it never walks the filesystem. On a source registered moments earlier (0 pages), the --full branch runs reindex-code, gbrain prints "No code pages to reindex", finishes in about a second, and the index stays empty. The page-creating walk (sync --strategy code) only runs on the incremental path.

This also contradicts the skill's own documented contract: the --full help text says "First-run; full walk + reindex" — but the code does reindex only, no walk.

Fix

--full runs the file-walk sync first (creating/refreshing pages), then reindex-code for the full re-embed. Incremental keeps the walk only. This matches the documented "full walk + reindex" contract and is correct for both freshly-registered and already-populated sources.

Verification

Reproduced and fixed end-to-end: with a freshly-registered source, --full on the unpatched code finished in about a second with 0 pages; with the fix it runs the real walk and the source fully populates (hundreds of pages, multi-minute walk as expected).

Notes

• Companion PR: #1583 (a classifier false-broken-db bug found during the same investigation; that one gates this skill from even reaching the orchestrator inside web-app repos).
• Secondary observation: the code stage reported OK with page_count=0. Worth considering a WARN/fail in the verdict block when a code sync completes with 0 pages on a non-empty repo, so this class of silent emptiness can't recur unnoticed. Not included here to keep the PR focused.

[jbetala7]

The behavior change looks right, but this needs a regression test before it is safe to keep. The previous bug was just the --full branch selecting reindex-code without first running sync --strategy code, so a fake gbrain in test/gstack-gbrain-sync.test.ts can assert the call order for --full is sync --strategy code ... then reindex-code ..., while incremental mode still calls only sync --strategy code. That would catch the empty-first-index regression without needing a real multi-minute gbrain walk.

[garrytan]

Thanks @jetsetterfl — gbrain-sync --full empty-index fix shipped in v1.43.2.0 post-Daegu wave (#1642).