feat: add frontstage management surface mock

[huangruiteng]

Summary

• add an ops-only management surface mock that maps the existing goal channel projection into Mission Bar, Team Roster, Ticket Board, Gate Inbox, Cadence/Budget, and Evidence Timeline
• keep the mock read-only and derived from goal_channel_projection_v0 instead of introducing a parallel state model
• add frontstage route smoke anchors and update the interaction baseline docs

Validation

• npm run build
• npm run smoke:frontstage-route
• npm run smoke:frontstage-design-baseline
• git diff --check
• loopx check --scan-path apps/dashboard/src/views/frontstage-page.tsx --scan-path apps/dashboard/smoke/frontstage-route-smoke.ts --scan-path docs/product/frontstage-dashboard-interaction-baseline.md

[huangruiteng]

Findings: none.

Validation:

• Merged PR feat: add frontstage management surface mock #693 head locally into the current origin/main merge result: no conflicts.
• npm --prefix apps/dashboard run smoke:frontstage-route on the current-main merge result.
• npm --prefix apps/dashboard run build on the current-main merge result.
• npm --prefix apps/dashboard run smoke:frontstage-design-baseline on the PR worktree.
• git diff --check HEAD on the current-main merge result.
• loopx check --scan-path apps/dashboard/src/views/frontstage-page.tsx --scan-path apps/dashboard/smoke/frontstage-route-smoke.ts --scan-path docs/product/frontstage-dashboard-interaction-baseline.md

Note: loopx check only reports the existing duplicate index rows warning for loopx-meta; the public/private scan is clean. The new management surface remains read-only and projection-backed from goal_channel_projection_v0, with no browser-side source of truth or write path. Decision: approved for self-merge. GitHub does not allow this account to approve its own PR, so I am recording the maintainer review here before merge.