[codex] Expose service catalog context diagnostics

[xu16601526267]

Summary

This PR exposes the AIMA service context needed to diagnose UI/CLI catalog and overlay mismatches.

What changed

• records catalog load time in app context
• adds service_context to system.status
• includes the same context in diagnostics bundles
• includes service context in catalog status
• reports data_dir, overlay_dir, catalog load time, latest overlay mtime, and a reload hint when overlays are newer than the loaded catalog

Why

When the UI service is long-running or running as a different user, catalog overlays may be edited in a different data directory or after the service loaded its catalog. Without explicit context, users and agents cannot tell which overlay/data dir the UI is actually using.

Validation

• go test ./cmd/aima -run TestServiceContextReportsStaleOverlayHint -count=1
• git diff --check

[xu16601526267]

Linux target validation passed on aitopatom-5ba7 (qujing@222.128.15.222:22222, Linux 6.11.0-1016-nvidia, aarch64) with temporary user-local go1.25.0 linux/arm64.

Validation run:

• git diff --check origin/develop...HEAD
• go test ./cmd/aima ./internal/knowledge ./internal/runtime -count=1
• go test ./... -count=1

Remote logs:

• related package logs: /home/qujing/aima-pr-ready-validation/logs-20260515T172839Z
• full package logs: /home/qujing/aima-pr-ready-validation/logs-full-20260515T172935Z