Remove agent-harness old context tools

[julwrites]

Deleted .cursorrules, docs/security/PERMISSIONS.md, .claude/hooks/session-start.sh, scripts/hooks/session_start.py and templates/task.md. Also cleaned up .claude/settings.json to reflect that the "SessionStart" hook is removed. This completes the cleanup for lingering agent-harness files related to task tracking and memory/context management.

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PR created automatically by Jules for task 17272153194099288075 started by @julwrites

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