Add quality gates, role library, and templates for team lifecycle v3

- Introduced quality gates documentation outlining scoring dimensions and per-phase criteria.
- Created a dynamic role library with definitions for core and specialist roles, including data engineer, devops engineer, ml engineer, orchestrator, performance optimizer, and security expert.
- Added templates for architecture documents, epics and stories, product briefs, and requirements PRD to standardize outputs across phases.

.claude/skills/team-tech-debt/role-specs/validator.md

@@ -70,6 +70,9 @@ Execute 4-layer validation (all commands in worktree):
     run_in_background: false
   })
   ```
+- Re-run validation checks after fix attempt
+  })
+  ```
 - Re-run checks after fix attempt
 
 ## Phase 4: Compare & Report