Build context-priority local CLI and brutalist launch demo

ventures/context-priority/sample.jsonl

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+{"role":"user","content":"Ship a migration plan. Never delete customer records."}
+{"role":"assistant","content":"Constraint accepted: preserve every customer record."}
+{"role":"user","content":"Check the schema."}
+{"role":"assistant","content":"Reading schema.","tool_calls":[{"id":"schema-1","type":"function","function":{"name":"read_file","arguments":"schema.sql"}}]}
+{"role":"tool","tool_call_id":"schema-1","content":"customers(id, email, created_at)"}
+{"role":"assistant","content":"Add the index concurrently; retain all rows."}
+{"role":"user","content":"Aside: what should the mascot wear?"}
+{"role":"assistant","content":"A very large green hat. This does not affect the migration."}
+{"role":"user","content":"Continue with the rollback checklist."}
+{"role":"assistant","content":"Rollback removes the new index only, never customer data."}