docs: stabilization directive + TRUTH document + AI session prompts + dockerignore

- STABILIZATION_DIRECTIVE.md: feature freeze rules, banned actions, priorities
- TRUTH.md: single source of truth for system state (crate counts, store counts)
- AI_SESSION_PROMPTS.md: three-layer prompt system for AI sessions
- Industry agent delivery design spec
- Stabilization test suite for regression prevention
- Delete stale ISSUE-TRACKER.md
- Add .dockerignore for container builds
- Add brainstorm session artifacts

.superpowers/brainstorm/1909-1775055381/waiting-kb-ui.html

@@ -0,0 +1,3 @@
+<div style="display:flex;align-items:center;justify-content:center;min-height:60vh">
+  <p class="subtitle">正在准备知识库 UI 布局方案...</p>
+</div>