docs+ci(predictive-echo): CI package-suite step, invariants, changeset

ci.yml runs the xterm-zerolag-input suite (Layers 1-3) after the root
npm ci (workspaces hoisting; no separate install). CLAUDE.md and
architecture-invariants.md rewrite the codex echo story: predictive
write-through with the wire-neutrality, separate-bundle, composer-gate,
baseY and blank-neutral invariants spelled out; the single-source section
now covers both vendor bundles and why their entry points differ.
Changeset: minor for aicodeman + xterm-zerolag-input.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

docs/architecture-invariants.md

@@ -22,7 +22,7 @@ Implementation detail extracted from `CLAUDE.md` so that file stays small enough
 
 **External CLI modes (OpenCode, Codex, Gemini, Antigravity)**: `isExternalCliMode()` in `session.ts` (`mode === 'opencode' || 'codex' || 'gemini' || 'antigravity'`) gates Claude-specific behavior — Ralph tracker, BashToolParser, token/CLI-info parsing, and ❯-prompt readiness detection are all skipped (these CLIs render their own TUIs; readiness = output stabilization instead). All four modes **require tmux — no direct PTY fallback** — because secrets are injected via `tmux setenv` (socket-scoped `${this.tmux()} setenv`, never on the spawn command line): OpenCode gets `OPENCODE_CONFIG_CONTENT` etc., Codex gets `OPENAI_API_KEY`/`CODEX_API_KEY`/`CODEX_HOME` (`setCodexEnvVars`), Gemini gets `GEMINI_API_KEY`/`GOOGLE_API_KEY`/`GOOGLE_CLOUD_PROJECT`/`GOOGLE_APPLICATION_CREDENTIALS`/`GOOGLE_GENAI_USE_VERTEXAI` etc. (`setGeminiEnvVars`, all in `tmux-manager.ts`). Codex specifics: command built by `buildCodexCommand()` (`--model`, `resume <id>`, `--dangerously-bypass-approvals-and-sandbox` from the `codexConfig` payload / `codexDangerouslyBypassApprovals` app setting; `renderMode` is schema-coerced to `'hybrid'`, the only supported mode). Gemini specifics: command built by `buildGeminiCommand()` (`--skip-trust` always, `--approval-mode <default|auto_edit|yolo|plan>` defaulting to `yolo` for parity with Claude's `--dangerously-skip-permissions`, `--model`, `--resume` from the `geminiConfig` payload); availability via `GET /api/gemini/status` — session/quick-start routes fail with `OPERATION_FAILED` + install hint (`npm install -g @google/gemini-cli`) when missing. Codex AND Gemini export `COLORTERM=truecolor` + unset `NO_COLOR` (other modes unset `COLORTERM`); Gemini joins `isAltScreenStripMode()` (Codex/Claude/Gemini are Ink TUIs that repaint inline → strip alt-screen/`3J` so scrollback survives). Codex availability via `GET /api/codex/status`. Antigravity specifics: command built by `buildAntigravityCommand()` (`--model`, `--conversation <id>` resume, `--dangerously-skip-permissions` from the `antigravityConfig` payload); availability via `GET /api/antigravity/status` — routes fail with `OPERATION_FAILED` + install hint (`curl -fsSL https://antigravity.google/cli/install.sh | bash`) when missing. Unlike the other three it is NOT an npm package (standalone binary, `~/.local/bin/agy`), which is why `docker/agent.Dockerfile` installs it with its own `--dir /usr/local/bin` step rather than in the `npm install -g` line, and why it does NOT join `isAltScreenStripMode()`. Frontend: run-mode dropdown → `runCodex()`/`runGemini()` in `session-ui.js` ("Run CX"/"Run GM" labels), App Settings → Codex CLI tab; Respawn/Ralph options are Claude-only, so session options open on the Summary tab for external CLI sessions. ⚠️ `run*()` MUST unwrap the `{success,data}` envelope (`(await res.json()).data.available` / `data.data.sessionId`) — reading the raw shape silently breaks the run. Tests: `test/run-mode-ui.test.ts` + `test/gemini-mode.test.ts` (vm-sandbox harness, no real DOM).
 
-**Codex input path (issues #218/#219/#220/#222)**: the local-echo overlay is **DISABLED for codex-mode sessions** (`_updateLocalEchoState` in terminal-ui.js, same branch as shell). Codex's composer is interactive per keystroke: typing "/" pops a live-filtering command picker (#222 was "picker never appears" because the "/" sat in the overlay until Enter), the composer grows/rewraps as it fills (#220: a long typed prompt existed ONLY in the overlay DOM, so codex never grew the composer), arrows and Ctrl+Backspace edit server-side state (#218: arrows were forwarded to an EMPTY composer while the typed text sat pending; the `\x08` control-char flush then left the overlay stateless so `\x7f` was swallowed as "nothing to remove"), and pastes arrive bracketed (#219: `terminal.paste()` wraps in `\x1b[200~..201~`, which the multi-byte-ESC branch forwarded WITHOUT flushing pending text, so the paste landed before it). The shared overlay branch (claude/gemini/opencode still buffer) gained three fixes: bracketed pastes flush pending text first, composer nav keys (`isComposerNavKey` allowlist in `CodemanTerminalInput` — arrows/Home/End/Delete/PgUp/PgDn incl. modifiers, deliberately excluding DA/CPR/DSR query responses) flush and hand the session to **pass-through** (plain PTY echo until Enter/Ctrl+C, because after cursor movement the append-only overlay cannot track edits), and a backspace that finds no overlay state is FORWARDED instead of swallowed. ⚠️ **Codex drops keystrokes that arrive in the same PTY read as a bracketed paste** (upstream `bottom_pane/paste_burst.rs` holds rapid chars for paste classification; verified against codex 0.147.0 by writing `hello\x1b[200~PASTED\x1b[201~` into the tmux client PTY in one write → composer shows only `PASTED`, while a 100ms gap yields `helloPASTED`), so the flush sends the typed text immediately and delays the paste sequence by 80ms — the same two-phase shape as the Enter branch's delayed `\r`. Related protocol fact: xterm.js sends `0x08` for Ctrl+Backspace, which codex's keymap binds to delete-ONE-char (`ctrl(Char('h'))`); real word-delete needs the kitty CSI-u encoding (`\x1b[127;5u`), which xterm.js 6.0.0 cannot emit (kitty support lands in 6.1.0-beta) — an upstream limitation, not a Codeman bug. E2E technique: codex 0.147 reaches its composer with any dummy key in `$CODEX_HOME/auth.json` (`{"OPENAI_API_KEY":"sk-test-..."}`), so a real TUI can be driven headlessly (envOverrides `CODEX_HOME` rides the `CODEX_*` allowlist) without real credentials. Tests: `test/local-echo-codex-gating.test.ts` (vm harness: nav-key classifier truth table, per-mode gating, flush helper, pass-through routing).
+**Codex input path (issues #218/#219/#220/#222)**: codex-mode sessions use **predictive write-through echo, never the buffer overlay**. The buffer overlay stays disabled exactly as 1.12.2 left it (`_updateLocalEchoState` in terminal-ui.js, same branch as shell; `_localEchoEnabled` remains false for codex), and the additive `_localEchoPolicy` field selects `'predict'` for codex when `localEchoEnabled` is on. Codex's composer is interactive per keystroke: typing "/" pops a live-filtering command picker (#222 was "picker never appears" because the "/" sat in the overlay until Enter), the composer grows/rewraps as it fills (#220: a long typed prompt existed ONLY in the overlay DOM, so codex never grew the composer), arrows and Ctrl+Backspace edit server-side state (#218: arrows were forwarded to an EMPTY composer while the typed text sat pending; the `\x08` control-char flush then left the overlay stateless so `\x7f` was swallowed as "nothing to remove"), and pastes arrive bracketed (#219: `terminal.paste()` wraps in `\x1b[200~..201~`, which the multi-byte-ESC branch forwarded WITHOUT flushing pending text, so the paste landed before it). The shared overlay branch (claude/gemini/opencode still buffer) gained three fixes: bracketed pastes flush pending text first, composer nav keys (`isComposerNavKey` allowlist in `CodemanTerminalInput` — arrows/Home/End/Delete/PgUp/PgDn incl. modifiers, deliberately excluding DA/CPR/DSR query responses) flush and hand the session to **pass-through** (plain PTY echo until Enter/Ctrl+C, because after cursor movement the append-only overlay cannot track edits), and a backspace that finds no overlay state is FORWARDED instead of swallowed. ⚠️ **Codex drops keystrokes that arrive in the same PTY read as a bracketed paste** (upstream `bottom_pane/paste_burst.rs` holds rapid chars for paste classification; verified against codex 0.147.0 by writing `hello\x1b[200~PASTED\x1b[201~` into the tmux client PTY in one write → composer shows only `PASTED`, while a 100ms gap yields `helloPASTED`), so the flush sends the typed text immediately and delays the paste sequence by 80ms — the same two-phase shape as the Enter branch's delayed `\r`. Related protocol fact: xterm.js sends `0x08` for Ctrl+Backspace, which codex's keymap binds to delete-ONE-char (`ctrl(Char('h'))`); real word-delete needs the kitty CSI-u encoding (`\x1b[127;5u`), which xterm.js 6.0.0 cannot emit (kitty support lands in 6.1.0-beta) — an upstream limitation, not a Codeman bug. E2E technique: codex 0.147 reaches its composer with any dummy key in `$CODEX_HOME/auth.json` (`{"OPENAI_API_KEY":"sk-test-..."}`), so a real TUI can be driven headlessly (envOverrides `CODEX_HOME` rides the `CODEX_*` allowlist) without real credentials. **Predictive write-through echo invariants** (the codex echo mode, `PredictiveEchoAddon` in `packages/xterm-zerolag-input`): (1) the onData hook `_predictHookOnData` is a PLAIN STATEMENT between the buffer block and Normal Mode — no `return`, try/catch-wrapped, never touches `_pendingInput` — so the wire path is byte-identical with the predictor active, absent or throwing (pinned at vm level and by an end-to-end trace-equality E2E); (2) it ships as a SEPARATE bundle `vendor/xterm-predictive-echo.js` so the zerolag bundle stays byte-identical, and a missing/broken bundle degrades codex to plain 1.12.2 echo (`typeof PredictiveEchoOverlay !== 'undefined'` guard); (3) predictions paint only while the cursor sits on the measured composer row (`isCodexComposerRow`, `CODEX_COMPOSER_ROW_RE = /^› /` — matches the empty-composer placeholder, typing, and the slash picker; rejects modal rows and 2-space wrapped continuation rows, the #220 ghost zone, which deliberately fall back to real echo); (4) reconciliation reads the PARSED buffer with `baseY + row` (xterm's `cursorY` is baseY-relative; `viewportY` only coincides while scrolled to bottom), confirms prefix-only on cell match PLUS cursor advance, cascades only on TWO consecutive foreign NON-BLANK passes (blanks are neutral: codex clears its placeholder on first echo), and TTL-bounds the rest; (5) the per-device `localEchoEnabled` toggle is the kill switch returning exact 1.12.2 behavior. Measured constants + fixtures: `docs/predictive-echo-plan.md`, recorded via `scripts/dev/record-codex-frames.mjs` through the production tmux+strip pipeline. Tests: `test/local-echo-codex-gating.test.ts` (vm harness: nav-key + predict classifier truth tables, policy matrix, wire-neutrality pins), `packages/xterm-zerolag-input/test/` (addon laws, real-fixture replay, seeded fuzz), `test/codex-predictive-echo.test.ts` (E2E vs real codex incl. byte-identity + 300ms-RTT).
 
 ### Remote sessions over SSH
 
@@ -275,7 +275,7 @@ Target: 20 sessions, 50 agent windows at 60fps. Limits in `src/config/`: termina
 
 ### xterm-zerolag-input is single-source
 
-**`xterm-zerolag-input` is single-source — edit the package, then rebuild the bundle** — the local-echo overlay source lives ONLY in `packages/xterm-zerolag-input/src/` (`zerolag-input-addon.ts`; also published to npm as a standalone library — see README "Published Packages"). It is bundled (esbuild → IIFE, with appended `window.LocalEchoOverlay` aliases) into the **gitignored** `src/web/public/vendor/xterm-zerolag-input.js` by `scripts/postinstall.js` (for dev/`tsx`) and into `dist/.../vendor/` by `scripts/build.mjs` (the `xterm-zerolag-input` esbuild step, for prod). `app.js` only **consumes** it via `new LocalEchoOverlay(terminal)` — there is NO inline copy to keep in sync. So: change behavior in the package source, then re-run the bundle step (`npm install` reruns postinstall; `npm run build` for prod); **never hand-edit `app.js` for overlay behavior or commit the gitignored vendor bundle**. A public-API break in the package still warrants a separate `xterm-zerolag-input` version bump in the changeset. Always test on mobile after touching it. See `docs/local-echo-overlay-plan.md`.
+**`xterm-zerolag-input` is single-source — edit the package, then rebuild the bundles** — BOTH echo addons live ONLY in `packages/xterm-zerolag-input/src/` (also published to npm as a standalone library — see README "Published Packages") and are bundled into TWO **gitignored** vendor files with DIFFERENT entry points: `vendor/xterm-zerolag-input.js` (buffer overlay, entry `zerolag-input-addon.ts`, `window.LocalEchoOverlay` alias) and `vendor/xterm-predictive-echo.js` (codex write-through, entry `predictive-echo-addon.ts`, `window.PredictiveEchoOverlay` alias) — dev by `scripts/postinstall.js` (reruns on `npm install`), prod by `scripts/build.mjs`. The separate entries are DELIBERATE: adding exports to the package's `index.ts` cannot change the zerolag bundle's bytes, which is what keeps predictive-echo changes structurally unable to regress buffer mode (verified sha256-identical at introduction). `app.js`/terminal-ui.js only **consume** the addons via `new LocalEchoOverlay(terminal)` / `new PredictiveEchoOverlay(terminal)` — there is NO inline copy to keep in sync. **Never hand-edit `app.js` for overlay behavior or commit the gitignored vendor bundles.** A public-API break in the package still warrants a separate `xterm-zerolag-input` version bump in the changeset. Always test on mobile after touching it. See `docs/local-echo-overlay-plan.md` (buffer mode) and `docs/predictive-echo-plan.md` (predict mode).
 
 ### node-pty's macOS spawn-helper must be executable