docs: lowercase internal docs + migrate website docs to public-docs/ (#634)

* docs: rename to lowercase + drop leftover plans

Rename docs in docs/ to lowercase kebab-case for consistency and update
all references in CLAUDE.md, CONTRIBUTING.md, CHANGELOG.md,
packages/server/CLAUDE.md, and inter-doc links.

Drop two leftover design plan docs:
- docs/ATTACHMENT_BASED_REVIEW_CONTEXT_PLAN.md
- docs/plan-approval-normalization.md

* docs: drop stale uppercase entries from case-insensitive rename

* feat(website): power /docs from public-docs/ markdown tree

Move website docs out of TSX route components and into a root-level
public-docs/ directory of plain markdown files with frontmatter
(title, description, nav, order).

- Add packages/website/src/docs.ts loader using import.meta.glob with
  ?raw to compile the markdown into the bundle at build time.
- Replace the 9 hand-written docs/*.tsx routes with a single $.tsx
  catch-all that renders any slug via react-markdown.
- Drive the docs sidebar nav from frontmatter order/nav.
- Auto-discover docs routes in vite.config.ts so the sitemap stays in
  sync without manual edits.

* fix(website): bind dev server to 0.0.0.0 so port collisions trigger fallback

`host: "127.0.0.1"` (or unset) lets macOS coexist with another process
holding an IPv6 dual-stack `*:8082` socket, so Vite never sees
EADDRINUSE and silently binds alongside it. Forcing IPv4 wildcard
makes the conflict real, and Vite's default `strictPort: false`
falls through to the next free port.

* fix(website): restore docs page styling after markdown migration

Add a .docs-prose class that mirrors the styling the original
docs/*.tsx components hand-rolled (h1/h2/h3 sizes, paragraph/list
spacing, link colors, code blocks, callout-style blockquotes).

ReactMarkdown was emitting unstyled HTML because the previous
wrapper class only had inline-code rules — headings and code
blocks fell back to user-agent defaults.

CONTRIBUTING.md

@@ -27,10 +27,10 @@ If you want to propose a direction change, start a conversation.
 Please read these first:
 
 - [README.md](README.md)
-- [docs/ARCHITECTURE.md](docs/ARCHITECTURE.md)
-- [docs/DEVELOPMENT.md](docs/DEVELOPMENT.md)
-- [docs/CODING_STANDARDS.md](docs/CODING_STANDARDS.md)
-- [docs/TESTING.md](docs/TESTING.md)
+- [docs/architecture.md](docs/architecture.md)
+- [docs/development.md](docs/development.md)
+- [docs/coding-standards.md](docs/coding-standards.md)
+- [docs/testing.md](docs/testing.md)
 - [CLAUDE.md](CLAUDE.md)
 
 ## What is most helpful
@@ -105,7 +105,7 @@ npm run dev:website
 npm run cli -- ls -a -g
 ```
 
-Read [docs/DEVELOPMENT.md](docs/DEVELOPMENT.md) for build-sync gotchas, local state, ports, and daemon details.
+Read [docs/development.md](docs/development.md) for build-sync gotchas, local state, ports, and daemon details.
 
 ## Multi-platform testing
 
@@ -132,7 +132,7 @@ If you touch protocol or shared client/server behavior, read the compatibility n
 
 Paseo has explicit standards. Follow them.
 
-The full guide lives in [docs/CODING_STANDARDS.md](docs/CODING_STANDARDS.md).
+The full guide lives in [docs/coding-standards.md](docs/coding-standards.md).
 
 ## PR checklist