Rebrand CommGate to gsmnode and adopt new design system

Rename the whole project from CommGate to gsmnode and re-skin every
surface onto the new signal-green + ink design system (Space Grotesk /
IBM Plex Sans / JetBrains Mono, flat surfaces, two-arrow routing mark,
lowercase gsm+node wordmark).

- Web App + API panel: rewrite token layer, gn-* utilities, data-gsm-theme,
  new logo/favicon assets; both builds verified.
- Phone App (Flutter): green theme, new mark/wordmark widgets, adaptive
  launcher icons; rename Android applicationId/package to app.gsmnode.phone;
  bump AGP to 8.6.0 and google_fonts to 8.1.0; debug APK build verified.
- API Server (Go): panel routes, User-Agent, health service id, branding.
- Home Assistant Plugin: rename integration domain sms_gateway to gsmnode
  (folder, DOMAIN, services, entity ids, classes); py_compile verified.
- Update all READMEs; add .gitignore (excludes Design/, build artifacts).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Home Assistant Plugin/custom_components/gsmnode/client.py

@@ -0,0 +1,105 @@
+"""Async client for the gsmnode API Server (shared by the UI integration)."""
+from __future__ import annotations
+
+import aiohttp
+
+from homeassistant.core import HomeAssistant
+from homeassistant.helpers.aiohttp_client import async_get_clientsession
+
+
+class GsmNodeAuthError(Exception):
+    """Raised when the API Server rejects the credentials."""
+
+
+class GsmNodeConnectionError(Exception):
+    """Raised when the API Server can't be reached or returns an error."""
+
+
+class GsmNodeClient:
+    """Talks to the API Server: login, send SMS, place calls, health."""
+
+    def __init__(
+        self,
+        hass: HomeAssistant,
+        api_base: str,
+        email: str,
+        password: str,
+        device_id: str | None = None,
+    ) -> None:
+        self._session = async_get_clientsession(hass)
+        self._api_base = api_base.rstrip("/")
+        self._email = email
+        self._password = password
+        self.device_id = device_id
+        self._token: str | None = None
+
+    async def login(self) -> None:
+        """Authenticate and cache the JWT."""
+        try:
+            async with self._session.post(
+                f"{self._api_base}/api/auth/login",
+                json={"email": self._email, "password": self._password},
+            ) as resp:
+                if resp.status == 401:
+                    raise GsmNodeAuthError("invalid credentials")
+                if resp.status != 200:
+                    raise GsmNodeConnectionError(f"HTTP {resp.status}")
+                data = await resp.json()
+                self._token = data.get("access_token")
+                if not self._token:
+                    raise GsmNodeAuthError("no token in response")
+        except aiohttp.ClientError as err:
+            raise GsmNodeConnectionError(str(err)) from err
+
+    async def _post(self, path: str, payload: dict) -> int:
+        headers = {"Authorization": f"Bearer {self._token}"} if self._token else {}
+        async with self._session.post(
+            f"{self._api_base}{path}", json=payload, headers=headers
+        ) as resp:
+            return resp.status
+
+    async def _send(self, path: str, payload: dict) -> None:
+        """POST with auth, re-logging in once on a 401."""
+        try:
+            if not self._token:
+                await self.login()
+            status = await self._post(path, payload)
+            if status == 401:
+                await self.login()
+                status = await self._post(path, payload)
+        except aiohttp.ClientError as err:
+            raise GsmNodeConnectionError(str(err)) from err
+        if status not in (200, 201, 202):
+            raise GsmNodeConnectionError(f"{path} -> HTTP {status}")
+
+    async def send_sms(
+        self,
+        phone_numbers: list[str],
+        message: str,
+        device_id: str | None = None,
+        sim_number: int | None = None,
+    ) -> None:
+        """Queue an outbound SMS."""
+        payload: dict = {"phone_numbers": phone_numbers, "text_message": message}
+        dev = device_id or self.device_id
+        if dev:
+            payload["device_id"] = dev
+        if sim_number is not None:
+            payload["sim_number"] = sim_number
+        await self._send("/api/messages", payload)
+
+    async def place_call(self, phone_number: str, device_id: str | None = None) -> None:
+        """Queue an outbound phone call."""
+        payload: dict = {"phone_number": phone_number}
+        dev = device_id or self.device_id
+        if dev:
+            payload["device_id"] = dev
+        await self._send("/api/calls", payload)
+
+    async def health(self) -> bool:
+        """Return True if the API Server's health endpoint responds OK."""
+        try:
+            async with self._session.get(f"{self._api_base}/api/health") as resp:
+                return resp.status == 200
+        except aiohttp.ClientError:
+            return False