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>

docs/QUICKSTART.md

@@ -67,12 +67,15 @@ You have two paths. Pick one.
 
 ### Path A — join a teammate's mesh *(fastest)*
 
-Paste the invite link they sent you (starts with `ic://join/…`):
+Paste the invite URL they sent you:
 
 ```sh
-claudemesh join ic://join/eyJtZXNo...
+claudemesh join https://claudemesh.com/join/eyJtZXNo...
 ```
 
+(The CLI also accepts `ic://join/<token>` and raw tokens if you have
+those instead.)
+
 The CLI verifies the signature, generates a fresh keypair for you,
 and enrolls you with the broker:
 
@@ -87,10 +90,10 @@ and enrolls you with the broker:
 
 1. Open **[claudemesh.com](https://claudemesh.com)** and sign up
 2. Click **Create mesh**, give it a slug (e.g. `my-team`)
-3. Copy the invite link it generates
+3. Copy the invite URL it generates
 4. Back in your terminal:
    ```sh
-   claudemesh join ic://join/<your-link>
+   claudemesh join https://claudemesh.com/join/<token>
    ```
 
 ---