feat: trusted employee memory and coordinated learning

[0YHR0]

Summary

• Derive employee/position memory identity from pinned Run Agent Version and active company appointment, not caller-provided IDs.
• Capture durable learning from successful winning coordinated work items after task completion and optional deliverable acceptance.
• Require human review for work-item learning; deduplicate replay even after rejection/revocation.
• Keep legacy shared company/project recall and reviewer isolation.

Validation

• 2507 tests passed, 304 skipped locally.
• 30 new employee memory regression tests.
• Ruff passed.

Scope

Private music production integration is separate. No music provider credentials or private environment addresses are included.