Reclaim ACP Jobs and configurable agentlet capacity

[Yuqing (mydmdm)]

Summary

• make Agenetes own one-shot Job teardown and wait for exact Agentlet process reclamation on completion, failure, cancellation, or early iterator return
• make Agentlet stop idempotent and confirmed, compensate failed session connections, and return redacted structured capacity diagnostics
• add an owner-only persisted maximum-agent setting (default 10, any positive safe integer) that applies to the supervised daemon after restart; remote daemons remain CLI-controlled

Validation

• pnpm typecheck
• pnpm format
• pnpm lint:fix (passes with 350 pre-existing warnings)
• Agenetes instance tests: 23 passed
• ACP driver placement/recovery tests: 20 passed
• server functional-text/runtime-config tests: 30 passed
• web General Settings tests: 2 passed
• Agentlet CLI/daemon integration tests: 11 passed
• full server suite: 2,415 passed, 28 skipped, 2 todo
• full web suite: 3,019 passed

Notes

• The setting is intentionally restart-only; saving it does not restart the daemon.
• No daemon/Agenetes configuration handshake is introduced.

Closes #235