Keep ticket IDs out of comments, commits, and PR copy.

Branch names still carry the ticket; the code and PR prose should not.

Co-authored-by: Cursor <cursoragent@cursor.com>

AGENTS.md

@@ -46,6 +46,8 @@ priors — they reflect deliberate decisions.
 6. **No new pathname-sniffing chrome.** Compose chrome via group/nested
    layouts, not `usePathname()` checks. (`ConditionalNavigation` is the
    sole tolerated exception — it carries SSR session state.)
+7. **No Linear ticket IDs in comments, commits, or PR copy.** Branch names
+   still carry `CR-<n>`. See `coding-guidelines.mdc`.
 
 ## Legacy / scaffolding