feat(cli): accept https://claudemesh.com/join/<token> invite URL format

Pairs with claudemesh-2's new /join/[token] landing page. Users can
now paste a clickable HTTPS URL instead of the dev-only ic:// scheme.

apps/cli/src/invite/parse.ts — new extractInviteToken() handles
four input formats before handing the raw base64url token to the
existing parseInviteLink pipeline:
  - https://claudemesh.com/join/<token>   (primary, clickable)
  - https://claudemesh.com/<locale>/join/<token>   (i18n prefix)
  - ic://join/<token>                     (still supported, dev)
  - <raw-token>                           (last resort: bare base64url)

User-facing strings updated to the HTTPS form:
- cli help: "join <url>"
- install success message
- list (no-meshes) hint
- MCP server "no meshes" error
- README.md primary example
- docs/QUICKSTART.md Path A + Path B

Verified extractInviteToken() on all 4 formats — each returns the
same base64url token → same broker /join lookup.

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

apps/cli/src/mcp/server.ts

@@ -103,7 +103,7 @@ If you have multiple joined meshes, prefix the \`to\` argument of send_message w
     const { name, arguments: args } = req.params;
     if (config.meshes.length === 0) {
       return text(
-        "No meshes joined. Run `claudemesh join <invite-link>` first.",
+        "No meshes joined. Run `claudemesh join https://claudemesh.com/join/<token>` first.",
         true,
       );
     }