Add automation and retrieval integration guides

[hyungchulc]

Summary

• document bounded POSIX cron, macOS launchd, and Codex Scheduled Task maintenance
• add runnable scheduler examples with privacy, locking, and fail-closed boundaries
• add the Memory Forest Retrieve host-gate profile and opt-in skill
• repair the retrieval SVG and add a current/future operating-model diagram

Validation

• make check (62 tests)
• public-release audit (83 files, no findings)
• git diff --check
• SVG XML validation and macOS Quick Look render inspection
• POSIX shell syntax and launchd plist lint