feat(ui): ScorePill for every grade chip

Confidence levels, the weekly score gain, target bands and lab range
flags were drawn by hand in two looks: a /15 wash without border in the
mood boards, a /10 wash with a /40 border on the correlation and trend
cards, and medium confidence was blue on one card and amber on the
next. They now render through one ScorePill (rounded, xs, soft wash,
tone success / info / warning / destructive / neutral, optional tabular
figures) with one confidence scale. The target band keeps its own
AA-tuned tokens in the shared anatomy. A structural test refuses a new
hand-rolled grade chip.

src/app/globals.css

@@ -232,7 +232,7 @@
   /*
    * v1.28.17 — the sleep-stage IN_BED fill. Distinct from `--dracula-comment`
    * above (an orphaned token — no `@theme` utility was ever generated for
-   * it, per the `confidence-badge.ts` note — and its `#9aa3b3` value never
+   * it — and its `#9aa3b3` value never
    * matched the classic Dracula "Comment" blue-grey this chart actually
    * paints). Minted here instead of retuning the unrelated token, so this
    * default carries the exact hex the stacked bar hardcoded before