centralize guides and rails under mosaic with runtime compatibility links

STANDARDS.md

@@ -12,12 +12,14 @@ Master/slave model:
 2. Load project-local `AGENTS.md` next.
 3. Respect repository-specific tooling and workflows.
 4. Use lifecycle scripts when available (`scripts/agent/*.sh`).
+5. Use shared rails/guides from `~/.mosaic` as canonical references.
 
 ## Non-Negotiables
 
 - Data files are authoritative; generated views are derived artifacts.
 - Pull before edits when collaborating in shared repos.
 - Run validation checks before claiming completion.
+- Apply quality rails from `~/.mosaic/rails/` when relevant (review, QA, git workflow).
 - Avoid hardcoded secrets and token leakage in remotes/commits.
 - Do not perform destructive git/file actions without explicit instruction.
 
@@ -44,3 +46,8 @@ All runtime adapters should inject:
 - project `AGENTS.md`
 
 before task execution.
+
+Runtime-compatible guides and rails are hosted at:
+
+- `~/.mosaic/guides/`
+- `~/.mosaic/rails/`