docs: add stats dashboard design docs, plans, and knowledge base

- Stats dashboard redesign design and implementation plans
- Episode detail and Anki card link design
- Internal knowledge base restructure
- Backlog tasks for testing, verification, and occurrence tracking

docs/knowledge-base/README.md

@@ -0,0 +1,35 @@
+<!-- read_when: changing internal docs structure, adding guidance, or debugging doc drift -->
+
+# Knowledge Base Rules
+
+Status: active  
+Last verified: 2026-03-13  
+Owner: Kyle Yasuda  
+Read when: maintaining the internal doc system itself
+
+This section defines how the internal knowledge base is organized and maintained.
+
+## Read Next
+
+- [Core Beliefs](./core-beliefs.md) - agent-first operating principles
+- [Catalog](./catalog.md) - indexed docs and verification status
+- [Quality](./quality.md) - current doc and architecture quality grades
+
+## Policy
+
+- `AGENTS.md` is an entrypoint only.
+- `docs/` is the internal system of record.
+- `docs-site/` is user-facing; do not treat it as canonical internal design or workflow storage.
+- Internal docs should be short, cross-linked, and specific.
+- Every core internal doc should include:
+  - `Status`
+  - `Last verified`
+  - `Owner`
+  - `Read when`
+
+## Maintenance
+
+- Update the relevant internal doc when behavior or workflow changes.
+- Add new docs to the [Catalog](./catalog.md).
+- Record architectural quality drift in [Quality](./quality.md).
+- Keep stale docs obvious; do not leave ambiguity about whether a page is trustworthy.