feat: UI polish — chat redesign, spiral loader, smooth upward animation

[quiet-node]

Summary

• Chat view redesign: user messages in right-aligned bubbles, AI responses as plain text (no bubble, full-width), copy button always visible for both (left for AI, right for user)
• 9-dot spiral loading indicator: replaces 3-dot bounce — brand color sweeps top-right → outer ring → center at 110ms/step, holds 200ms, pauses 500ms, then repeats; 3px dots with 3px gaps, no shadows
• Smooth upward-anchor animation: eliminates all visual jumping when the overlay is spawned above a text selection
  • On submit, the native window immediately pre-expands to max height so streaming text fills a fixed canvas (no incremental upward repositioning)
  • Explicit minHeight is set on the outer container before every set_window_frame call to prevent a WKWebView viewport-lag flash that caused the ask bar to jump to the top of the window on submit

Test plan

• All 240 Vitest tests pass (bun run test)
• bun run validate-build passes with zero warnings/errors
• Open overlay normally (no anchor) — input bar appears, chat works, copy buttons always visible
• Open overlay above selected text (upward anchor) — submit a message and verify the window expands smoothly upward with no flash/jump
• Stream a long response in upward-anchor mode — text fills from bottom, no repositioning jitter
• Spiral indicator appears while waiting for first token, disappears when streaming starts

🤖 Generated with Claude Code

[quiet-node]

Code review

Found 2 issues:

1. TypingIndicator restart cycle is untested — violates 100% coverage mandate (CLAUDE.md says "100% code coverage is mandatory. Any new or modified code — frontend or backend — must maintain 100% coverage across lines, functions, branches, and statements. PRs that drop below 100% coverage will not be merged.")

The inner schedule callback that resets the spiral after PAUSE_MS (lines 92–96) is never executed by any test. The furthest any test advances is STEP_MS * 8 + FADE_MS (880 ms), which triggers setDimmed(true) but stops before the PAUSE_MS (500 ms) inner timer fires. Lines 92–96 (currentStep = 0, setStep(0), setDimmed(false), schedule(tick, STEP_MS)) are unreachable under the current test suite, failing the 100% line/branch/statement requirement.

thuki/src/components/TypingIndicator.tsx

Lines 90 to 97 in 1f9ad57

	setDimmed(true);
	schedule(() => {
	currentStep = 0;
	setStep(0);
	setDimmed(false);
	schedule(tick, STEP_MS);
	}, PAUSE_MS);
	}, FADE_MS);

Missing test coverage in:

thuki/src/components/__tests__/TypingIndicator.test.tsx

Lines 75 to 84 in 1f9ad57

	it('all dots go idle after center hold (FADE_MS after reaching center)', () => {
	const { container } = render(<TypingIndicator />);
	act(() => {
	vi.advanceTimersByTime(STEP_MS * 8 + FADE_MS);
	});
	const dots = container.querySelectorAll('.rounded-full');
	Array.from(dots).forEach((dot) => {
	expect(dot.classList.contains('bg-primary')).toBe(false);
	});
	});

2. Dead group class on user bubble wrapper (CLAUDE.md says "zero tolerance for dead code")

The group class on the user message wrapper exists solely to drive group-hover visibility on CopyButton. This PR removes opacity-0 group-hover:opacity-100 from CopyButton (copy button is now always visible), but leaves group on the wrapper with a misleading comment "group enables legacy hover compat". Nothing in the subtree consumes group-hover anymore.

thuki/src/components/ChatBubble.tsx

Lines 68 to 70 in 1f9ad57

	/* User bubble — max-width capped, group enables legacy hover compat */
	<div className="group flex flex-col max-w-[80%]">
	<div className="chat-bubble chat-bubble-user relative px-4 py-2.5 text-sm leading-relaxed select-text rounded-2xl rounded-br-md">

🤖 Generated with Claude Code

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