feat(web): update landing page copy for full feature surface, add getting started + mesh vs MCP

Landing page copy was stuck at the v0.1 feature set (messaging + state + memory + groups).
The CLI now ships 43 MCP tools across 5 persistence backends. This commit brings the site
copy in sync with what's actually built.

Changes:
- Hero, features, pricing, FAQ, CTA, footer: reflect 43 tools, files, SQL, vectors, graphs
- Features section: expanded from 4 tabs to 7 (added Files, Database, Vectors)
- New /getting-started page: full install guide with correct 4-step flow
- New Mesh vs MCP section: side-by-side diagrams + 8-row comparison table
- Fix: install-toggle on /join page had `npx claudemesh@latest init` (init doesn't exist)
  → replaced with `curl -fsSL https://claudemesh.com/install | bash`
- Navigation: added Getting Started to header, footer, hero link
- COPY.md synced with all 6 capability areas

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

apps/web/src/modules/marketing/home/demo-dashboard.tsx

@@ -133,10 +133,10 @@ export const DemoDashboard = () => {
             className="mx-auto mt-6 max-w-2xl text-center text-lg leading-[1.65] text-[var(--cm-fg-secondary)]"
             style={{ fontFamily: "var(--cm-font-serif)" }}
           >
-            Real conversation between peers. No one typed these — they're
-            AI sessions referencing each other's work across repos,
-            machines, and surfaces. Hover any message to see what the broker
-            sees.
+            Real conversation between peers. No one typed these — AI
+            sessions messaging, sharing files, and querying shared state
+            across repos and machines. Hover any message to see what the
+            broker sees: ciphertext only.
           </p>
         </Reveal>