feat(neo): grok-exact theme + xterm.js evidence harness (neo-go-tui task 2)

[code-yeongyu]

Summary

Plan task 2 of .omo/plans/neo-go-tui.md: the grok-exact theme package for the neo Go TUI, plus the xterm.js evidence-harness core that all later TUI-visual QA in the plan runs through. Additive only — nothing outside packages/neo changes.

Changes

• internal/theme: 24-bit palette transcribed from the grok capture research (grok-night default + grok-day), lipgloss v2 styles (surfaces, text tiers, accents, borders, footer/hint, tool-row glyphs, braille spinner), loader honoring settings.json theme + ~/.senpi/agent/themes custom themes; NO_COLOR + 256-color fallbacks.
• packages/neo/qa/xterm-render.mjs: .ans → self-contained HTML review page + per-cell grid JSON + assertion helpers, on the root-hoisted @xterm/headless (no new dep); visual-claims.json manifest + verify-manifest mode failing on missing frames/triplet legs/assertions.
• Hidden --theme-sample flag on cmd/senpi-neo renders the QA panel.

QA / Evidence

Evidence: .omo/evidence/task-2-neo-go-tui.md (+ red/, red-posthoc/, gates/, qa/ artifact dirs) in the work worktree.

• Golden tests assert exact truecolor SGR through the harness cell grid; hexes derived from captures, never implementation output. 22 test functions / 28 subtests, all green (-v capture archived).
• tmux QA (verbatim plan scenario): rendered panel captured with capture-pane -e, every extracted fg/bg hex asserted ∈ grok palette via the parsed cell grid; full triplet archived. 256-color fallback frame has zero truecolor escapes, no crash.
• Integrity round: an initial RED artifact was found unreliable (timestamp mismatch) by an adversarial audit and superseded by two labeled post-hoc proofs (implementation-aside compile RED restored byte-identical by sha256; one-hex mutation proof failing with exact cell coordinates). Re-audit verdict: real.
• Harness self-test 6/6 (corrupted fixture fails loudly; verify-manifest negatives fail); npm run check exit 0; real ~/.senpi untouched (hash receipt).

Risks

• Goldens could drift from grok captures if palette edits bypass the research files — mitigated by capture-derived golden constants and the visual-claims manifest gate that later waves (tasks 20/21, F3) re-run.

Secret safety

No secrets in code, fixtures, or evidence; QA sandboxed.

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Summary by cubic

Implements the exact grok theme for the neo Go TUI and adds an xterm.js evidence harness for visual QA. Locks in truecolor palette accuracy (grok-night default, grok-day optional) with 256/NO_COLOR fallbacks and a reproducible sample panel.

• New Features

  • packages/neo/internal/theme: exact 24‑bit palette, lipgloss v2 styles (surfaces, text tiers, accents, borders), braille spinner, and tool-row glyphs.
  • Theme loader honors settings.json theme and ~/.senpi/agent/themes custom themes; default is grok-night.
  • Truecolor rendering with downgrade to ANSI256/NO_COLOR via colorprofile.
  • Hidden --theme-sample flag in cmd/senpi-neo to render a deterministic QA panel.
  • packages/neo/qa/xterm-render.mjs: .ans → HTML review + per-cell grid JSON + assertion helpers; visual-claims.json with verify-manifest to fail on missing frames/triplet legs/assertions.
  • Golden tests verify exact hexes through the parsed cell grid; loader and harness self-tests included.

• Dependencies

  • Uses root-hoisted @xterm/headless (no new npm dep in this package).
  • Uses charm.land/lipgloss/v2 and github.com/charmbracelet/colorprofile.
  • Additive change confined to packages/neo.

^{Written for commit 3118bca. Summary will update on new commits.}