Implement planning pass with submit_plan tool in ai.py
Add _PLANNING_SYSTEM_PROMPT to prompts.py
Skip survey pass for targets below minimum size threshold
Implement _run_survey() and submit_survey tool in ai.py
Wire survey output into dir loop system prompt
Add _SURVEY_SYSTEM_PROMPT to prompts.py
Add low_confidence_entries() query to CacheManager
Add confidence fields to file and dir cache schemas
Update dir loop prompt to set confidence on cache writes