Mine the user's Claude Code chat history for ideas/feedback/pain about a specific topic, synthesize a ranked themed brief, then optionally cross-reference against existing docs and file tickets. Use when the user says "review all my chats/sessions for ideas about X", "what have I said about Y across my history", "mine my conversations for feedback on Z", or wants to harvest scattered design notes / complaints / abandoned threads about a focus area. This is FOCUSED topical mining (local, not shared) — distinct from the shareable pattern-mining in tools/session-mining/README.md.