fix(tui): restore foreground hue step for tab status colors - #49899

Why

In dark mode the session tab rail's running spinner, unread marker, and ! / ? attention markers render in a near-background shade, so a busy tab shows a barely visible flickering dot instead of a spinner. The /btw spinner and mini-mode status colors have the same problem.

Two theme refactors landed today a few hours apart. #49820 flipped hue steps to follow the mode's contrast direction, so in dark themes 100 is now the light end and 800 the dark end, and it moved the text.status.* tokens from .800 to .200 accordingly. #49846 then removed text.status.* and rewrote its consumers as raw hue lookups, but used the pre-flip step [800]:

-  const activeNumber = () => theme.text.status.running
+  const activeNumber = () => theme.hue.accent[800]   // dark end in dark mode

The dialogs converted in the same commit correctly use [200]; these call sites were the stragglers.

What Changes

Every theme.hue.accent[800] / theme.hue.interactive[800] status color moves to step 200, matching how the theme asset defines every other foreground token (text.base, text.feedback.*, text.formfield.* are all $hue.*.200). Light mode is unaffected in intent: its hue ramps are inverted in opencode.json, so 200 is the high-contrast foreground step in both modes.

Demo

Both halves run the identical Drive script (dark opencode theme, vertical tabs, 120×30, simulated model streaming a slow reply so the session stays busy). Left: origin/v2 at 7125f5f. Right: this branch. Cropped to the left 600px of each frame so the tab rail stays legible side by side.

Zoomed tab rail from the same runs — top is before, bottom is after:

Scope

Only the hue step at the call sites #49846 converted, plus the two tests that asserted on [800]. No theme schema or asset changes. Whether these should return to a semantic text.status token is a separate question for the theme work in flight.

Verification

cd packages/tui
bun run test test/component/session-tabs-status.test.tsx test/mini/theme.test.ts   # 26 pass
bun typecheck

End to end: the Drive before/after recording above, run against 7125f5f and this branch with the same script.