chore: add agentic tooling, cleanup

.crosslink/rules/tracking-relaxed.md

@@ -0,0 +1,11 @@
+## Crosslink (Available)
+
+Crosslink issue tracking is available but not required. Use it when it helps.
+
+```bash
+crosslink quick "title" -p <priority> -l <label>   # Create + label + work
+crosslink issue list -s open                              # See open issues
+crosslink issue close <id>                                # Close issue
+crosslink session work <id>                         # Mark focus
+crosslink session end --notes "..."                 # Save handoff
+```