Introduce a single nav-config module (webui/nav.py) driving grouped
navigation across the epic #631 Phase 1 information architecture:
Health, Traffic, Runtime/Sessions, Projects, Inventory, Timeline,
Policy (placeholder), and Insights (placeholder). The shell header now
carries a read-only environment badge (local/remote from WEBUI_HOST), a
mode: read-only badge, and a Docs link. Home summarizes the console
purpose, lists the Phase 1 surfaces by group, and links the MVP legacy
pages.
Not-yet-implemented surfaces (/sessions, /inventory, /timeline,
/policy, /insights) resolve to graceful read-only stub pages rather than
404s; their backing views land in later child issues of #631 (inventory
surfaces backed by #636). Mutating methods on stub routes still fail
closed with read-only-mvp. No privileged action controls are added.
Adds tests/test_webui_shell.py covering nav groups, badge presence,
environment classification, docs link, stub routes (200 + read-only),
and home content. Updates docs/webui-local-dev.md with the new routes
and a Phase 1 shell section.
Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>