Lift the answer-quality popover above the follow-up cards; redraw the quality icons

[jaketracey]

What

• Stacking: the answer-quality dropdown was painted under the "Ask next" follow-up cards (see Jake's screenshot). Every late-arriving block fades up with rp-answer-tail, whose entrance animation used animation-fill-mode: both. A filled-forward opacity/transform interpolation leaves each block a permanent stacking context, so the z-30 popover inside the actions row could never rise above the sibling blocks that follow it. The keyframes only declare from, so backwards ends on the same pixels and releases the context once the entrance is over. Same one-word change to rp-answer-in (the answer body) for the same reason.
• Icons: the four confidence glyphs move to the 24-unit grid and 1.7 stroke of the neighbouring answer-action icons, with the stroke thinning as the box grows so every size lands at the same optical weight. The exclamation dots are zero-length round-capped strokes instead of 0.15-radius filled circles, which rendered below a pixel and left the triangle reading as a bare outline.

Verified

• deno task check green (typecheck, lint, fmt, 215 tests).
• Chrome, local build, real GRDC answer with a Low confidence score and three follow-ups:
  • 1280px layout viewport: dropdown hit-tests on top of all three follow-up cards; the actions row reports transform: none after its entrance. Forcing animation-fill-mode: both back on reproduces the trapped panel (row keeps a transform, the block below hit-tests on top).
  • True 390px layout viewport (iframe probe, header relaxed locally and reverted): bottom sheet opens at z-90, scrollWidth equals innerWidth.
  • Both on the default palette and the Observatory dark palette.
• Isolated probe page confirms the mechanism in Chrome: both lets a later sibling paint over a z-30 child popover; backwards does not.

🤖 Generated with Claude Code

https://claude.ai/code/session_01GYuuU1yPFeGKZpkwW2mLs6

---

^{Need help on this PR? Tag @codesmith-bot with what you need. Autofix is disabled.}