fix(web): start CTAs → /auth/register + GitHub link → claude-intercom OSS

All conversion CTAs were pointing to the dead github.com/claudemesh/
claudemesh repo or # hash fragments. Landing is the primary funnel for
v0.1.0 — every "Start" button is a conversion-critical surface.

Fixes:
- Header "Start free" → /auth/register
- Header GitHub nav item → REMOVED (kept the icon button, repointed)
- Hero "Start free" → /auth/register
- Pricing 6× CTAs: Solo/Pro/Plus/Team/Business → /auth/register,
  Enterprise → /contact
- CTA footer "Star on GitHub" → /auth/register ("Start free")
- BeyondTerminal "Read the protocol spec" → /auth/register
  ("Get on the mesh")

GitHub reinstated as a dedicated icon button in the header right side,
pointing to https://github.com/alezmad/claude-intercom — the MIT OSS
foundation claudemesh is built on. Honest provenance: claude-intercom
is the local peer-mesh gift to the community, claudemesh is the hosted
cross-machine extension.

Tooltip: "Built on claude-intercom · MIT open source".

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/web/src/modules/marketing/home/pricing.tsx

@@ -9,8 +9,8 @@ const TIERS = {
       name: "Solo",
       desc: "Run the broker on your laptop. Pair your Claude Code sessions across repos.",
       price: "Free",
-      cta: "Install locally",
-      href: "https://github.com/claudemesh/claudemesh",
+      cta: "Start free",
+      href: "/auth/register",
     },
     {
       name: "Pro",
@@ -18,7 +18,7 @@ const TIERS = {
       price: "$12",
       note: "per month",
       cta: "Start free trial",
-      href: "#",
+      href: "/auth/register",
     },
     {
       name: "Plus",
@@ -26,7 +26,7 @@ const TIERS = {
       price: "$24",
       note: "per month",
       cta: "Start free trial",
-      href: "#",
+      href: "/auth/register",
     },
   ],
   team: [
@@ -35,23 +35,23 @@ const TIERS = {
       desc: "Self-hosted broker. SSO, shared presence, team audit log, 25 peers.",
       price: "$99",
       note: "per month · unlimited peers",
-      cta: "Get started",
-      href: "#",
+      cta: "Start free",
+      href: "/auth/register",
     },
     {
       name: "Business",
       desc: "Multi-region brokers, retention controls, Slack/Linear bridges.",
       price: "$499",
       note: "per month",
-      cta: "Get started",
-      href: "#",
+      cta: "Start free",
+      href: "/auth/register",
     },
     {
       name: "Enterprise",
       desc: "Air-gapped deploy, custom SAML, dedicated support, SOC 2 pack.",
       price: "Contact",
       cta: "Contact sales",
-      href: "#",
+      href: "/contact",
     },
   ],
 };