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/README.md

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+# Role Library - Team Lifecycle v3
+
+Dynamic role specification library for team-lifecycle-v3. Role definitions are loaded at runtime to extend the built-in role detection table.
+
+## Purpose
+
+- Extend role inference beyond hardcoded defaults
+- Support domain-specific specialist roles
+- Enable dynamic role injection based on task keywords
+- Maintain backward compatibility with v2 core roles
+
+## Role Categories
+
+### Core Pipeline Roles (v2 inherited)
+- analyst, writer, planner, executor, tester, reviewer
+- architect, fe-developer, fe-qa
+
+### Specialist Roles (v3 new)
+- **orchestrator**: Complex task decomposition and parallel coordination
+- **security-expert**: Security analysis and vulnerability scanning
+- **performance-optimizer**: Performance profiling and optimization
+- **data-engineer**: Data pipeline and schema design
+- **devops-engineer**: Infrastructure as code and CI/CD
+- **ml-engineer**: Machine learning pipeline implementation
+
+## Dynamic Role Injection
+
+Specialist roles are injected at runtime when coordinator detects matching keywords in task descriptions:
+
+| Keywords | Injected Role |
+|----------|---------------|
+| security, vulnerability, OWASP | security-expert |
+| performance, optimization, bottleneck | performance-optimizer |
+| data, pipeline, ETL, schema | data-engineer |
+| devops, CI/CD, deployment, docker | devops-engineer |
+| machine learning, ML, model, training | ml-engineer |
+| orchestrate, complex, multi-module | orchestrator |
+
+## Role Definition Format
+
+Each role definition is a `.role.md` file with YAML frontmatter + description.
+
+### Schema
+
+```yaml
+---
+role: <role-name>
+keywords: [<keyword1>, <keyword2>, ...]
+responsibility_type: <Orchestration|Code generation|Validation|Read-only analysis>
+task_prefix: <PREFIX>
+default_inner_loop: <true|false>
+category: <domain-category>
+capabilities: [<capability1>, <capability2>, ...]
+---
+
+<Role description and responsibilities>
+```
+
+## Usage
+
+Role library is loaded by coordinator during Phase 1 (Requirements Collection) to extend role detection capabilities. Custom roles override built-in roles with same `role` identifier.
+
+## Extensibility
+
+Users can add custom role definitions by creating new `.role.md` files in this directory following the schema above.