⚡ Bolt: Fix Router network config and lifecycle safety

- Configures `aiohttp.ClientSession(trust_env=True)` to respect proxy settings, which is critical for CI environments.
- Adds defensive lazy initialization of `self.session` in `_generate` and `_generate_stream` to prevent crashes if `startup()` is bypassed in tests.
- Re-verifies code style with `black`.

Co-authored-by: ZeyuChen <1371212+ZeyuChen@users.noreply.github.com>

Author: google-labs-jules[bot]

fastdeploy/router/router.py

@@ -101,7 +101,7 @@ def __init__(self, args):
     async def startup(self):
         """Initialize resources"""
         if self.session is None:
-            self.session = aiohttp.ClientSession()
+            self.session = aiohttp.ClientSession(trust_env=True)
             logger.info("Router session initialized")
 
     async def shutdown(self):
@@ -240,7 +240,8 @@ async def _generate(
         self, modified_request, urls, return_result_url_index=-1, endpoint="v1/chat/completions"
     ) -> ORJSONResponse:
         if self.session is None:
-            raise RuntimeError("Router session not initialized")
+            logger.warning("Router session not initialized, creating a new one")
+            self.session = aiohttp.ClientSession(trust_env=True)
 
         timeout = aiohttp.ClientTimeout(total=self.timeout)
         tasks = [self.session.post(f"{url}/{endpoint}", json=modified_request, timeout=timeout) for url in urls]
@@ -273,7 +274,8 @@ async def _generate_stream(
     ):
         async def stream_results():
             if self.session is None:
-                raise RuntimeError("Router session not initialized")
+                logger.warning("Router session not initialized, creating a new one")
+                self.session = aiohttp.ClientSession(trust_env=True)
 
             timeout = aiohttp.ClientTimeout(total=self.timeout)
             tasks = [self.session.post(f"{url}/{endpoint}", json=modified_request, timeout=timeout) for url in urls]