feat: expose inverse, strikethrough, faint, invisible and cursorVisible in snapshots

[ThomasK33]

Closes #15

Summary

Snapshots now expose the remaining SGR cell attributes and DECTCEM cursor visibility, so coder/agent-tty (coder/agent-tty#171) can render reverse video, strikethrough, dim and hidden text, and hide the cursor.

• SnapshotCell gains optional faint (SGR 2), inverse (SGR 7), invisible (SGR 8) and strikethrough (SGR 9).
  • Same convention as bold/italic/underline: the key is present with true only when set, and omitted otherwise.
  • inverse is the raw attribute. foreground/background are not swapped.
• TerminalSnapshot gains cursorVisible?: boolean. The native binding always sets it (true/false); the type is optional for compatibility.
• Values come from libghostty-vt's C API at the pinned commit: GhosttyStyle.{faint,inverse,invisible,strikethrough} via the existing ghostty_grid_ref_style call, and ghostty_terminal_get(GHOSTTY_TERMINAL_DATA_CURSOR_VISIBLE). No new libghostty entry points.
• README documents the snapshot fields. CHANGELOG.md is not hand-edited: the release-changelog workflow generates it with Communique on release/v* PRs.

Existing fields are unchanged.

Tests (written first, red before the native change)

• Per attribute (inverse 7/27, strikethrough 9/29, faint 2/22, invisible 8/28): unstyled cell, set, attribute-specific reset, set again, SGR 0 reset.
• All attributes combined on one cell (ESC[1;2;3;4;7;8;9m).
• Inverse keeps the unswapped ESC[31;42m colors.
• cursorVisible: default true, ESC[?25l gives false (with and without includeCells), ESC[?25h gives true.

Validation

Gate	Result
npm run build:libghostty (pinned Ghostty 48ccec18, Zig 0.15.2)	pass
npm run build:native	pass, no warnings
npm run build	pass
npm run typecheck (and an ad hoc tsc run including test/)	pass
npm test	13/13 pass (7 new)
npm run smoke	pass

The repo has no lint script.

Dogfood

A standalone Node ESM script imports @coder/libghostty-vt-node (linked to this branch's build), feeds ESC[?25l, then ESC[31;42;7mI ESC[27mi ESC[0m ESC[9mS ESC[29ms ESC[2mF ESC[22mf ESC[8mH ESC[28mh ESC[1;2;7;8;9mX ESC[0mx, then ESC[?25h, and prints snapshot({ includeCells: true }):

Script

import { createTerminal, getNativeInfo } from "@coder/libghostty-vt-node";

const term = createTerminal({ cols: 40, rows: 4 });
const steps = [];
const snap = (label) => {
  const s = term.snapshot({ includeCells: true });
  steps.push({ label, cursorVisible: s.cursorVisible, cursorRow: s.cursorRow, cursorCol: s.cursorCol });
  return s;
};
snap("initial");
term.feed("\x1b[?25l");
snap("after ESC[?25l");
term.feed("\x1b[31;42;7mI\x1b[27mi\x1b[0m \x1b[9mS\x1b[29ms \x1b[2mF\x1b[22mf \x1b[8mH\x1b[28mh \x1b[1;2;7;8;9mX\x1b[0mx");
term.feed("\x1b[?25h");
const s = snap("after ESC[?25h");
console.log(JSON.stringify({ ghostty: getNativeInfo().ghosttyCommit, cursorSteps: steps, line0: s.visibleLines[0].text, cells: s.cells }, null, 1));
term.dispose();

Output (one cell per line):

{"cursorSteps":[{"label":"initial","cursorVisible":true,"cursorRow":0,"cursorCol":0},{"label":"after ESC[?25l","cursorVisible":false,"cursorRow":0,"cursorCol":0},{"label":"after ESC[?25h","cursorVisible":true,"cursorRow":0,"cursorCol":14}],"line0":"Ii Ss Ff Hh Xx"}
{"row":0,"col":0,"text":"I","width":1,"inverse":true,"foreground":"#cc6666","background":"#b5bd68"}
{"row":0,"col":1,"text":"i","width":1,"foreground":"#cc6666","background":"#b5bd68"}
{"row":0,"col":2,"text":" ","width":1}
{"row":0,"col":3,"text":"S","width":1,"strikethrough":true}
{"row":0,"col":4,"text":"s","width":1}
{"row":0,"col":5,"text":" ","width":1}
{"row":0,"col":6,"text":"F","width":1,"faint":true}
{"row":0,"col":7,"text":"f","width":1}
{"row":0,"col":8,"text":" ","width":1}
{"row":0,"col":9,"text":"H","width":1,"invisible":true}
{"row":0,"col":10,"text":"h","width":1}
{"row":0,"col":11,"text":" ","width":1}
{"row":0,"col":12,"text":"X","width":1,"bold":true,"faint":true,"inverse":true,"invisible":true,"strikethrough":true}
{"row":0,"col":13,"text":"x","width":1}

The uppercase cells carry the attribute, and the lowercase cells after each reset do not. I keeps #cc6666 on #b5bd68 (palette 1 on palette 2), the same as unswapped i.

Notes for agent-tty

• Apply reverse video by swapping foreground/background yourself, substituting your default colors when either one is absent.
• invisible cells still report their text, and visibleLines/getVisibleText() still include hidden text (unchanged). Skip drawing glyphs for invisible cells.
• Unchanged limitation: cells only contains cells with text. Erased cells that have only a background color (for example, an ESC[K status bar fill) are not emitted.

---

Generated with xum • Model: anthropic:claude-opus-5-5 • Thinking: high

[ThomasK33]

@codex review

[ThomasK33]

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[ThomasK33]

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[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-09-24T12:06:46.439329Z	f19f8e5	Manual request
🔒 Security Review	✅ Completed 2026-09-24T12:11:42.671596Z	f19f8e5	Manual request

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Codex Review: Didn't find any major issues. Another round soon, please!

Reviewed commit: f19f8e5924

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