fix(chat): feed title model raw turns instead of post-build_context messages

_generate_title was receiving the full messages list from build_context,
which prepends RAG snippets, RSS excerpts, URL content, and briefing
article dumps INTO the user-role message string. The role=="user" filter
inside _generate_title then handed that composite blob (capped at 300
chars) to gemma3:4b as "the user's message", so the background model
was titling conversations based on article excerpts instead of what the
user actually typed — producing wildly wrong titles like "Briefing
Profile Preferences & Schedule" for a plain calendar query. See #109.

Pass the raw history + user_content + assistant reply instead.

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

src/fabledassistant/services/generation_task.py

@@ -527,9 +527,22 @@ async def run_generation(
         should_gen_title = not conv_title or (msg_count > 0 and msg_count % 10 == 0)
 
         if should_gen_title:
-            title_messages = messages + [
-                {"role": "assistant", "content": buf.content_so_far}
+            # Feed the title model the *raw* conversation turns only — never
+            # the post-build_context ``messages`` list. ``build_context``
+            # prepends RAG snippets, RSS excerpts, URL content, and briefing
+            # article dumps INTO the user message string itself, so filtering
+            # by role="user" downstream still surfaces that noise as the
+            # "user's message". That pollution caused wildly-wrong titles
+            # (bug #109) — the small background model was staring at article
+            # excerpts instead of what the user actually typed. Pass the
+            # original history + the raw user_content + the assistant reply.
+            title_messages: list[dict] = [
+                {"role": m["role"], "content": m.get("content") or ""}
+                for m in history
+                if m.get("role") in ("user", "assistant")
             ]
+            title_messages.append({"role": "user", "content": user_content})
+            title_messages.append({"role": "assistant", "content": buf.content_so_far})
 
             async def _bg_title() -> None:
                 try: