feat:init,config_flow: YAML seed-only setup — an optional nvidia_shield block starts interactive SOURCE_IMPORT flows (parsed in async_setup), the import step guards duplicates by host/MAC-virtual unique_id and never re-seeds UI-configured hosts, protocol fields are prefill hints only (t30 U1)

custom_components/nvidia_shield/config_flow.py

@@ -471,6 +471,54 @@ class NvidiaShieldConfigFlow(config_entries.ConfigFlow, domain=DOMAIN):
             errors=errors,
         )
 
+    async def async_step_import(self, data):
+        """Seed an interactive flow from YAML (t30 U1, seed-only ruling).
+
+        The import validates the block and routes into the standard user
+        flow — pairing stays interactive, exactly one visit. Duplicate
+        guards: the block's host/MAC-virtual unique_id aborts when an
+        entry already holds it, and a UI-configured entry with the same
+        protocol/adb host is never re-seeded.
+        """
+        block = dict(data or {})
+        name = block.get("name") or DEFAULT_NAME
+        seed_unique_id = block.get("unique_id")
+        if not seed_unique_id:
+            host = block.get(CONF_ADB_HOST) or block.get(CONF_PROTOCOL_HOST)
+            seed_unique_id = f"yaml:{name}:{host or 'nohost'}"
+
+        # duplicate guards
+        yhost = block.get(CONF_ADB_HOST) or block.get(CONF_PROTOCOL_HOST)
+        for existing in self.hass.config_entries.async_entries():
+            ehost = existing.options.get(CONF_PROTOCOL_HOST) or existing.options.get(
+                CONF_ADB_HOST
+            )
+            if existing.unique_id == seed_unique_id or (
+                yhost and ehost == yhost
+            ):
+                _LOGGER.info(
+                    "nvidia_shield YAML seed for %r matches an existing "
+                    "entry — not re-seeded",
+                    name,
+                )
+                return self.async_abort(reason="already_configured")
+        await self.async_set_unique_id(seed_unique_id)
+        self._abort_if_unique_id_configured()
+
+        # route into the standard user flow (single interactive visit)
+        self._user_data = {
+            "name": name,
+            CONF_ADB_ENABLED: True,
+            CONF_ADB_HOST: block.get(CONF_ADB_HOST, ""),
+            CONF_ADB_PORT: block.get(CONF_ADB_PORT, DEFAULT_ADB_PORT),
+            # protocol prefill hints ONLY (pairing stays interactive)
+            CONF_PROTOCOL_HOST: block.get(CONF_PROTOCOL_HOST, ""),
+        }
+        self._discovered_host = self._user_data[CONF_PROTOCOL_HOST] or self._user_data[
+            CONF_ADB_HOST
+        ]
+        return await self.async_step_user(None)
+
     async def async_step_reauth(self, entry_data):
         """Device hard reset invalidated our certificates (review trigger)."""
         self._reauth_entry = self.hass.config_entries.async_get_entry(