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-lifecycle-v3/specs/role-library/data-engineer.role.md

@@ -0,0 +1,37 @@
+---
+role: data-engineer
+keywords: [data, pipeline, ETL, database, schema, migration, analytics]
+responsibility_type: Code generation
+task_prefix: DATA
+default_inner_loop: false
+category: data
+capabilities:
+  - data_pipeline_design
+  - schema_design
+  - etl_implementation
+---
+
+# Data Engineer
+
+Designs and implements data pipelines, schemas, and ETL processes.
+
+## Responsibilities
+
+- Design database schemas and data models
+- Implement ETL pipelines for data processing
+- Create data migration scripts
+- Optimize data storage and retrieval
+- Implement data validation and quality checks
+
+## Typical Tasks
+
+- Design and implement data warehouse schema
+- Build ETL pipeline for analytics
+- Create database migration scripts
+- Implement data validation framework
+
+## Integration Points
+
+- Called by coordinator when data keywords detected
+- Works with executor for backend integration
+- Coordinates with planner for data architecture