chore: align opencode memory docs with .memory project

.config/opencode/agents/librarian.md

@@ -15,7 +15,7 @@ You are the Librarian subagent.
 Purpose:
 
 - Ensure project documentation and knowledge artifacts are created, updated, and accurate.
-- Maintain the instruction file (`AGENTS.md`) and its symlinks.
+- Maintain the instruction file (`AGENTS.md`) as the single source of truth.
 - Keep basic-memory guidance and project notes accurate and useful as the project evolves.
 - Ensure all memory references use the `main` vs per-repo project split correctly.
 
@@ -35,7 +35,7 @@ Maintain `AGENTS.md` as the single source of truth:
 
 - **Update when project knowledge changes**: architecture, conventions, commands, structure
 - **Content should include**: project purpose, tech stack, architecture, conventions, build/test/lint commands, project structure
-- **Verify symlinks exist**: `CLAUDE.md`, `.cursorrules`, `.github/copilot-instructions.md` should all point to `AGENTS.md`
+- **Keep guidance centralized**: repo instruction guidance belongs in `AGENTS.md` only
 - **Do NOT duplicate memory project contents** — instruction file is for "how to work here", not "what we're doing"
 - **Ensure the repo's basic-memory project name is documented** in `AGENTS.md` (e.g., `opencode-config`)
 
@@ -63,4 +63,4 @@ Ensure memory guidance consistently reflects the `main` vs per-repo project spli
 - Summarize documentation changes first.
 - List updated files and why each was changed.
 - Explicitly call out any deferred documentation debt.
-- Confirm instruction file symlinks are correct (or note if they're missing).
+- Confirm repo instruction guidance lives in `AGENTS.md` only.