Fix streaming timeout and false-offline status indicator

- stream_chat and stream_chat_with_tools: remove read=300s per-chunk
  timeout, replace with read=None. In httpx streaming mode, the read
  timeout applies per-chunk — if Ollama pauses >300s while processing
  a large input context before the first token, it raises ReadTimeout,
  killing generation and leaving the assistant message as an empty stub.
  With read=None the stream is unbounded; connect=30s still guards the
  initial connection.

- chat_status_route: increase Ollama status check timeout 5s → 10s.
  When Ollama is busy processing a large prompt it can be slow to
  respond to /api/tags, causing the status indicator to briefly flip to
  "offline" even though generation is running normally.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/fabledassistant/routes/chat.py

@@ -328,7 +328,7 @@ async def chat_status_route():
         "default_model": default_model,
     }
     try:
-        async with httpx.AsyncClient(timeout=5.0) as client:
+        async with httpx.AsyncClient(timeout=10.0) as client:
             # Query installed models and loaded models in parallel
             tags_task = asyncio.create_task(client.get(f"{Config.OLLAMA_URL}/api/tags"))
             ps_task = asyncio.create_task(client.get(f"{Config.OLLAMA_URL}/api/ps"))

src/fabledassistant/services/llm.py

@@ -110,7 +110,9 @@ async def stream_chat(
     if options:
         merged_options.update(options)
     payload: dict = {"model": model, "messages": messages, "stream": True, "options": merged_options}
-    async with httpx.AsyncClient(timeout=httpx.Timeout(1800.0, connect=30.0, read=300.0)) as client:
+    # read=None: no per-chunk timeout — Ollama may pause for any duration while
+    # processing a large input context before the first token arrives.
+    async with httpx.AsyncClient(timeout=httpx.Timeout(connect=30.0, read=None, write=None, pool=30.0)) as client:
         async with client.stream(
             "POST",
             f"{Config.OLLAMA_URL}/api/chat",
@@ -164,7 +166,8 @@ async def stream_chat_with_tools(
     }
     if tools:
         payload["tools"] = tools
-    async with httpx.AsyncClient(timeout=httpx.Timeout(1800.0, connect=30.0, read=300.0)) as client:
+    # read=None: no per-chunk timeout for the same reason as stream_chat.
+    async with httpx.AsyncClient(timeout=httpx.Timeout(connect=30.0, read=None, write=None, pool=30.0)) as client:
         async with client.stream(
             "POST",
             f"{Config.OLLAMA_URL}/api/chat",