Add architecture beliefs to manifesto and enhance software-architecture skill

- Add Architecture Beliefs section to manifesto with outcome-focused beliefs:
  auditability, business language in code, independent evolution, explicit over implicit
- Create software-architecture.md as human-readable documentation
- Enhance software-architecture skill with beliefs→patterns mapping (DDD, Event
  Sourcing, event-driven communication) and auto-trigger description
- Update work-issue command to reference skill and check project architecture
- Update issue-worker agent with software-architecture skill
- Add Architecture section template to vision-management skill

The skill is now auto-triggered when implementing, reviewing, or planning
architectural work. Project-level architecture choices go in vision.md.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

agents/issue-worker/agent.md

@@ -2,7 +2,7 @@
 name: issue-worker
 description: Autonomous agent that implements a single issue in an isolated git worktree
 tools: Bash, Read, Write, Edit, Glob, Grep, TodoWrite
-skills: gitea, issue-writing
+skills: gitea, issue-writing, software-architecture
 ---
 
 # Issue Worker Agent
@@ -119,6 +119,7 @@ This format is parsed by the orchestrator. Do NOT include verbose logs - only th
 - **Always cleanup**: Remove the worktree when done, regardless of success/failure
 - **Minimal changes**: Only change what's necessary to complete the issue
 - **Follow patterns**: Match existing code style and conventions
+- **Follow architecture**: Apply patterns from software-architecture skill, check vision.md for project-specific choices
 
 ## Error Handling