Summary

gbrain sync --source <id> correctly tracks the per-source sync state
(last_commit, last_sync_at on the sources row) but does not
attribute imported pages to the named source — pages always land in
default. As a result, gbrain sources list shows 0 pages for any
source whose content arrives via sync, and source partitioning is
effectively non-functional for the sync path.

Repro

mkdir -p /tmp/foo && cd /tmp/foo && git init -q && echo "# hello" > a.md
git add . && git commit -qm init
gbrain sources add foo --path /tmp/foo --federated
gbrain sync --source foo
gbrain sources list

Expected:

foo  federated  1 pages  last sync ...

Actual (v0.21.0):

default  federated  N+1 pages
foo      federated  0 pages    last sync ...

Root cause

commands/sync.ts calls importFile/importFromFile without threading
sourceId:

• commands/sync.ts:464 — await importFile(engine, filePath, to, { noEmbed });
• commands/sync.ts:498 — await importFile(engine, filePath, path, { noEmbed });

core/import-file.ts:338 — importFromFile's opts type is
{ noEmbed?: boolean }. There's no source_id parameter, so the page
write defaults to 'default' regardless of which source the sync was
scoped to.

sourceId is otherwise correctly used for sync-state plumbing in
commands/sync.ts (readSyncAnchor, writeSyncAnchor,
readChunkerVersion, writeChunkerVersion — lines ~174-245). It just
never reaches the page-write call.

Suggested fix

1. Extend importFromFile opts to { noEmbed?: boolean; sourceId?: string }.
2. Inside importFromFile, pass source_id to the page write (default
   to 'default' when not provided, preserving current behavior).
3. In commands/sync.ts, pass { noEmbed, sourceId: opts.sourceId } at
   both importFile call sites.
4. Recommended: add --source <id> to gbrain import <dir> for parity
   — commands/import.ts likewise hard-codes attribution.

Adjacent observation

core/sync.ts:202-203 supports include/exclude glob filtering inside
isSyncable, but commands/sync.ts:354 constructs syncOpts as
opts.strategy ? { strategy: opts.strategy } : undefined —
include/exclude from source config are never plumbed through. Likely
a separate gap, but in the same area; could fold into the same fix or
split.

Version

gbrain 0.21.0