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.

packages/website/src/routes/docs.tsx

@@ -1,28 +1,21 @@
 import { createFileRoute, Link, Outlet } from "@tanstack/react-router";
+import { getDocs } from "~/docs";
 import "~/styles.css";
 
 export const Route = createFileRoute("/docs")({
   component: DocsLayout,
 });
 
-const navigation = [
-  { name: "Getting started", href: "/docs" },
-  { name: "Updates", href: "/docs/updates" },
-  { name: "Voice", href: "/docs/voice" },
-  { name: "Git worktrees", href: "/docs/worktrees" },
-  { name: "CLI", href: "/docs/cli" },
-  { name: "Skills", href: "/docs/skills" },
-  { name: "Providers", href: "/docs/providers" },
-  { name: "Configuration", href: "/docs/configuration" },
-  { name: "Security", href: "/docs/security" },
-  { name: "Best practices", href: "/docs/best-practices" },
-];
-
 const ACTIVE_OPTIONS_EXACT = { exact: true };
 const MOBILE_ACTIVE_PROPS = { className: "text-foreground" };
 const DESKTOP_ACTIVE_PROPS = { className: "bg-muted text-foreground" };
 
 function DocsLayout() {
+  const navigation = getDocs().map((doc) => ({
+    name: doc.frontmatter.nav,
+    href: doc.href,
+  }));
+
   return (
     <div className="min-h-screen bg-background">
       {/* Mobile header */}
@@ -31,7 +24,7 @@ function DocsLayout() {
           <img src="/logo.svg" alt="Paseo" className="w-6 h-6" />
           <span className="text-lg font-medium">Paseo</span>
         </Link>
-        <nav className="flex gap-4 mt-4">
+        <nav className="flex gap-4 mt-4 flex-wrap">
           {navigation.map((item) => (
             <Link
               key={item.href}
@@ -67,7 +60,7 @@ function DocsLayout() {
             ))}
           </nav>
         </aside>
-        <main className="flex-1 p-6 md:p-12 max-w-3xl prose">
+        <main className="flex-1 p-6 md:p-12 max-w-3xl docs-prose">
           <Outlet />
         </main>
       </div>