Release 0.2.2: Philosophy.jsx now renders mermaid (uses MarkdownPreview)

Philosophy.jsx parsed PHILOSOPHY.md with bare marked + dangerouslySet
InnerHTML, so ```mermaid fences fell through as <pre> blocks. Swapped
to MarkdownPreview, which already carries the lazy mermaid loader +
SVG render path used by the RFC body view. Pre-existing gap, surfaced
when an OHM deployment authored a mermaid block in its PHILOSOPHY_PATH
override.

PATCH per SPEC §20.2 — additive, no operator action required beyond
the routine rebuild + restart.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

CHANGELOG.md

@@ -23,6 +23,25 @@ skip versions are the composition of each intervening adjacent
 release's steps in order — no A-to-B path is pre-computed beyond
 that.
 
+## 0.2.2 — 2026-05-26
+
+**Patch — no operator action required.** Rebuild the frontend and
+restart per the routine deploy steps; no `.env` changes, no schema
+changes, no behavior changes a deployment would notice in steady
+state beyond the fix below.
+
+### Fixed
+
+- **Mermaid blocks rendered as raw code on `/philosophy`.**
+  `frontend/src/components/Philosophy.jsx` parsed PHILOSOPHY.md with
+  the bare `marked` import and `dangerouslySetInnerHTML`, so
+  ```` ```mermaid ```` fences fell through as `<pre>` blocks rather
+  than rendered diagrams. Swapped to `MarkdownPreview`, which already
+  carries the lazy mermaid loader + SVG render path used by the RFC
+  body view, so the philosophy surface now renders mermaid the same
+  way RFC bodies do. Pre-existing gap, surfaced when a deployment
+  authored a mermaid block in its `PHILOSOPHY_PATH` override.
+
 ## 0.2.1 — 2026-05-26
 
 **Patch — no operator action required.** Rebuild the frontend and