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>

manifesto.md

@@ -51,6 +51,20 @@ We believe AI fundamentally changes how software is built:
 
 - **Iteration speed is a competitive advantage.** The faster you can go from idea to deployed code to learning, the faster you improve. AI collapses the feedback loop.
 
+### Architecture Beliefs
+
+We believe certain outcomes matter more than others when building systems:
+
+- **Auditability by default.** Systems should remember what happened, not just current state. History is valuable - for debugging, compliance, understanding, and recovery.
+
+- **Business language in code.** The words domain experts use should appear in the codebase. When code mirrors how the business thinks, everyone can reason about it.
+
+- **Independent evolution.** Parts of the system should change without breaking other parts. Loose coupling isn't just nice - it's how small teams stay fast as systems grow.
+
+- **Explicit over implicit.** Intent should be visible. Side effects should be traceable. When something important happens, the system should make that obvious.
+
+See [software-architecture.md](./software-architecture.md) for the patterns we use to achieve these outcomes.
+
 ### Quality Without Ceremony
 
 - Ship small, ship often