fix: address PR review findings for Gemini run mode + Ralph todo-config

Gemini (PR #134) blockers:
- runGemini() now unwraps the {success,data} envelope: status check reads
  .data.available, quick-start reads data.data.sessionId (was reading the raw
  shape, so the Run-Gemini button could never start a session).
- setGeminiEnvVars() now uses the socket-scoped ${this.tmux()} setenv instead of
  bare tmux — Gemini/Google auth env vars were targeting the wrong tmux server
  and silently failing on every install.

Gemini parity polish:
- gemini tab-mode badge ('gm') + .tab-mode.gemini CSS; kill-dialog label
  'Kill Tmux & Gemini'; codeman doctor dependency-registry entry; export
  isGeminiAvailable from utils barrel; COLORTERM=truecolor + unset NO_COLOR;
  add gemini to isAltScreenStripMode (Ink TUI, repaints inline like Codex/Claude).
- Revert 4 system-routes.test.ts envelope assertions weakened to
  (body.message ?? body.error) back to (body.success === false).
- Add a runGemini() vm-sandbox test that drives the envelope path end-to-end.

Ralph todo-config (PR #135): maxTodos/todoExpirationMinutes are now persisted
and read back — surfaced via the loopState getter (RalphTrackerState) into
toState()/SSE broadcast and restored in restoreState(), mirroring maxIterations.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/tmux-manager.ts

@@ -720,7 +720,7 @@ function setCodexEnvVars(tmuxCmd: string, muxName: string): void {
  * Gemini Pro/Ultra users usually authenticate via cached Google login; these
  * variables cover API-key and Vertex AI paths without putting secrets in ps.
  */
-function setGeminiEnvVars(muxName: string): void {
+function setGeminiEnvVars(tmuxCmd: string, muxName: string): void {
   const sensitiveVars = [
     'GEMINI_API_KEY',
     'GEMINI_MODEL',
@@ -735,7 +735,7 @@ function setGeminiEnvVars(muxName: string): void {
     if (val) {
       const escaped = val.replace(/'/g, "'\\''");
       try {
-        execSync(`tmux setenv -t '${muxName}' ${key} '${escaped}'`, {
+        execSync(`${tmuxCmd} setenv -t '${muxName}' ${key} '${escaped}'`, {
           encoding: 'utf8',
           timeout: EXEC_TIMEOUT_MS,
           stdio: ['pipe', 'pipe', 'pipe'],
@@ -929,8 +929,8 @@ export class TmuxManager extends EventEmitter implements TerminalMultiplexer {
     const exports = [
       'export LANG=en_US.UTF-8',
       'export LC_ALL=en_US.UTF-8',
-      mode === 'codex' ? 'export COLORTERM=truecolor' : 'unset COLORTERM',
-      ...(mode === 'codex' ? ['unset NO_COLOR'] : []),
+      mode === 'codex' || mode === 'gemini' ? 'export COLORTERM=truecolor' : 'unset COLORTERM',
+      ...(mode === 'codex' || mode === 'gemini' ? ['unset NO_COLOR'] : []),
       'export CODEMAN_MUX=1',
       `export CODEMAN_SESSION_ID=${sessionId}`,
       `export CODEMAN_MUX_NAME=${muxName}`,
@@ -1034,7 +1034,7 @@ export class TmuxManager extends EventEmitter implements TerminalMultiplexer {
    * Configure Gemini-specific environment on a tmux session.
    */
   private _configureGemini(muxName: string): void {
-    setGeminiEnvVars(muxName);
+    setGeminiEnvVars(this.tmux(), muxName);
   }
 
   /**