[process-manager PM-11] Loopback transport + address-descriptor discovery + CLI degraded mode

[rickylabs]

Summary

Loopback TCP oRPC transport (single canonical transport, E6 unix-socket deferred) + address-descriptor discovery (KV + file) + the CLI degraded-mode fallback seam (OS-layer reads when the control plane is down).

Scope

• Archetype / area: packages/plugin-process-manager-core transport/discovery
• Part of Epic: NetScript Process Manager — bare-metal supervisor + admin console (pup/pm2 done right) #510
• Depends on: [process-manager PM-10] Control-plane oRPC service (PluginServiceContribution) #521 · Blocks: PM-25
• Acceptance documents that the control plane is network-reachable on 127.0.0.1 (TCP-only until E6's unix-socket upgrade) so token auth (PM-12) is understood as load-bearing, not defense-in-depth (F-5)

Design source

• research/design/d2-control-plane-contract.md §4 (D2-S4) · plan.md §4 PM-11, E6, R4

Acceptance criteria

• gate: address descriptor written to KV + file with 0o600 perms; discovery precedence tested
• gate: docs/README state the 127.0.0.1 reachability + token-auth-is-load-bearing posture explicitly
• gate: scoped check/lint/fmt wrappers green (--ext ts,tsx)

Non-scope

• Unix sockets (deferred, E6); remote/non-loopback bind (deny-remote default is PM-12).

Drift / Debt

• none