chore: add gitignore for mock-seed, roam CI workflow, formatting

- Add tools/mock-seed/ to .gitignore
- Add .github/workflows/roam.yml CI workflow
- Add .roam/fitness.yaml architectural fitness rules
- Rustfmt formatting fixes in show.rs and vector.rs
- Beads sync

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.gitignore

@@ -41,6 +41,9 @@ lore.config.json
 *.db-shm
 
 
+# Mock seed data
+tools/mock-seed/
+
 # Added by cargo
 
 /target