Slice 4 of Round 4 — the visible polish. With Slices 1–3 the agent
preamble + non-dismissible banner cover the "agent must know +
user must see" loop, but a closed HUD with no banner visible can
still hide the warning. This slice paints the menu-bar icon red so
the warning is glanceable from anywhere on the screen.
Option A from the slice plan (single-writer-safe):
- `MenuBarIconController.applyHealth(_ health: OverallHealth)` paints
`button.contentTintColor = NSColor.systemRed` for `.loud` and
`.critical`, clears the tint for `.ok` and `.soft`. Template images
recolor automatically with `contentTintColor` so no second icon
asset is needed.
- `currentHealth: OverallHealth?` exposed read-only for tests.
- `AppDelegate.runBootHealth` calls `menuBarController?.applyHealth(
snapshot.overallHealth)` after computing the degradation summary,
so the icon updates on every probe sweep (cold boot + Status panel
re-probe).
Single-writer invariant for HudState (HUD-08) is intact:
`contentTintColor` lives on `NSStatusItemButton`, not in HudState.
`scripts/check-single-writer-hudstate.sh` is green.
1 new test in MenuBarIconControllerTests:
* test_applyHealthTintsRedForLoudAndCritical — exercises all four
OverallHealth cases and asserts contentTintColor toggles correctly.
Boundary gates 18/18 green; App target compiles cleanly.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>