feat: wire librarian as the primary agent for documentation and instruction file maintenance

Expand librarian role to own cross-tool instruction file sync,
.memory/ file maintenance, and knowledge merge workflows. Lead
now proactively dispatches librarian in PHASE-WRAP and Documentation
Completion Gate instead of handling docs inline.

.config/opencode/commands/bootstrap-memory.md

@@ -60,10 +60,10 @@ constraints). Include rationale when known.
 - If research artifacts are discovered, create `.memory/research/<topic>.md`
   with findings and references.
 
-## Step 6: Create/update cross-tool instruction files
+## Step 6: Delegate instruction file creation to librarian
 
-After `.memory/knowledge.md` is populated, use it as the source of truth to
-create or update all cross-tool instruction files:
+After `.memory/knowledge.md` is populated, dispatch the `librarian` subagent to
+create or update all cross-tool instruction files from `.memory/knowledge.md`:
 
 - `AGENTS.md`
 - `CLAUDE.md`