feat(llm): search-first heuristic in chat tool_lines static block

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/fabledassistant/services/llm.py

@@ -620,6 +620,7 @@ async def build_context(
         "CRITICAL: Call the tool functions directly. NEVER write out function calls as text or code. NEVER describe what you would do — just do it.",
         "GROUNDING: When the user asks about their own data — tasks, notes, events, projects, news, anything stored in this system — call the relevant tool to see what actually exists before answering. Never assert facts about the user's data from memory, prior context, or assumption. If you are unsure whether something exists, check with a tool.",
         "HONESTY WHEN EMPTY: If a tool returns empty results (no matching tasks, no events in the date range, no search hits, no notes found), tell the user plainly that nothing matched. Do not fabricate example items, do not invent plausible-sounding meetings or deadlines to fill the response, and do not hedge with generic suggestions dressed up as real data. A direct 'you don't have anything on your calendar today' is always better than an invented event.",
+        "EXISTING WORK: When the user describes ongoing or completed work that references a specific project or task by name or partial name, call search_notes first to locate the existing item. Only call record_moment, create_task, or create_note if no matching task surfaces and the user confirms.",
     ]
     actions = [
         "create_note (also creates tasks — set status='todo')", "update_note", "delete_note",