fix: code-mode session creation uses idempotent ensure, run sequentially

- Use 'sessions ensure --name' instead of 'sessions new' so reopening a
  chat resumes the existing session instead of erroring on a name clash
- Create the session and run the prompt as separate sequential calls so
  the permission/command blocks render one at a time (not all at once)

apps/x/packages/core/src/agents/runtime.ts

@@ -1331,14 +1331,16 @@ The user has turned on **code mode** and the composer chip is set to **${agentDi
 1. By toggling the chip in the composer (preferred).
 2. By asking you directly in chat ("use codex", "switch to claude", "do this with ${otherDisplay}", etc.). When the user explicitly asks to use a different agent in the current message, honor that — use \`${otherAgent}\` instead of \`${codeMode}\` for this turn, and briefly mention they can also toggle it via the chip for stickiness.
 
-**Persistent session for this chat — session name: \`${sessionName}\`.** This chat uses one named agent session so the agent keeps context across your requests. The session must be created once before it can be used (\`-s\` only resumes; it does not create).
+**Persistent session for this chat — session name: \`${sessionName}\`.** This chat uses one named agent session so the agent keeps context across your requests. The session must exist before it can be prompted (\`-s\` only resumes; it does not create).
 
-**1. First coding action in this chat — create the session:**
+**1. First coding action in this chat — ensure the session exists:**
 
 \`\`\`
-npx acpx@latest --approve-all --cwd <workdir> <agent> sessions new --name ${sessionName}
+npx acpx@latest --approve-all --cwd <workdir> <agent> sessions ensure --name ${sessionName}
 \`\`\`
 
+(\`ensure\` creates the session if missing and reuses it if it already exists — safe to call when reopening this chat later.)
+
 **2. Then run the prompt:**
 
 \`\`\`
@@ -1351,6 +1353,8 @@ npx acpx@latest --approve-all --cwd <workdir> <agent> -s ${sessionName} "<prompt
 npx acpx@latest --approve-all --cwd <workdir> <agent> -s ${sessionName} "<prompt>"
 \`\`\`
 
+Run these as **separate, sequential** \`executeCommand\` calls — issue the \`sessions ensure\` call first and WAIT for it to finish, then issue the prompt call. Do NOT fire both in the same turn / batch.
+
 Where \`<agent>\` is either \`claude\` or \`codex\` — pick based on (in priority order): an explicit in-chat override → the chip setting (\`${codeMode}\`). Use \`${sessionName}\` exactly — do NOT invent a different name, and do NOT use \`exec\` (it is one-shot and forgets).
 
 If the user's message is clearly NOT a coding request (small talk, an unrelated question), answer directly without invoking the coding agent. Code mode signals readiness, not that every message must route through the agent.`;

apps/x/packages/core/src/application/assistant/skills/code-with-agents/skill.ts

@@ -62,14 +62,16 @@ Pick \`<session-name>\` — **stable for this whole chat**:
 - If the "# Code Mode (Active)" block gives a session name (e.g. \`rowboat-<runId>\`), use that exact name.
 - Otherwise pick one short, kebab-case name and **reuse it for every coding call this turn and in follow-ups** — never a new name each time.
 
-**\`-s\` resumes an existing session; it does NOT create one.** So create the session once at the start, then prompt:
+**\`-s\` resumes an existing session; it does NOT create one.** So ensure the session exists once at the start, then prompt:
 
-**1. First coding action in this chat — create the session:**
+**1. First coding action in this chat — ensure the session exists:**
 
 \`\`\`
-npx acpx@latest --approve-all --cwd <folder> <agent> sessions new --name <session-name>
+npx acpx@latest --approve-all --cwd <folder> <agent> sessions ensure --name <session-name>
 \`\`\`
 
+(\`ensure\` creates the session if missing and reuses it if it already exists — so reopening this chat later just resumes the same session instead of erroring.)
+
 **2. Then run the prompt:**
 
 \`\`\`
@@ -82,13 +84,15 @@ npx acpx@latest --approve-all --cwd <folder> <agent> -s <session-name> "<prompt>
 npx acpx@latest --approve-all --cwd <folder> <agent> -s <session-name> "<prompt>"
 \`\`\`
 
+**Run steps 1 and 2 as separate, sequential \`executeCommand\` calls.** Issue the \`sessions ensure\` call FIRST, wait for it to finish, and only THEN issue the prompt call. Do NOT fire both in the same turn / batch — each must surface and complete its own permission + command block before the next begins.
+
 Do NOT use \`exec\` — it is one-shot and forgets everything.
 
 Concrete example:
 
 \`\`\`
-# First coding message in the chat — create, then prompt:
-npx acpx@latest --approve-all --cwd "G:\\Blogging\\myblog" claude sessions new --name diskspace-check
+# First coding message in the chat — ensure the session, then prompt:
+npx acpx@latest --approve-all --cwd "G:\\Blogging\\myblog" claude sessions ensure --name diskspace-check
 npx acpx@latest --approve-all --cwd "G:\\Blogging\\myblog" claude -s diskspace-check "Check the system disk space and report total, used, and free space."
 
 # Follow-up in the same chat — reuse the session, no create:
@@ -97,7 +101,7 @@ npx acpx@latest --approve-all --cwd "G:\\Blogging\\myblog" claude -s diskspace-c
 
 ### Critical: flag order
 
-\`--approve-all\` and \`--cwd\` are GLOBAL flags and MUST appear BEFORE the agent name. \`sessions new --name <name>\` and \`-s <session-name>\` come AFTER the agent name:
+\`--approve-all\` and \`--cwd\` are GLOBAL flags and MUST appear BEFORE the agent name. \`sessions ensure --name <name>\` and \`-s <session-name>\` come AFTER the agent name:
 
 - ✓ Correct: \`npx acpx@latest --approve-all --cwd <folder> <agent> -s <session-name> "<prompt>"\`
 - ✗ Wrong:  \`npx acpx@latest <agent> --approve-all -s <name> "..."\` (will fail)
@@ -117,7 +121,7 @@ After the command finishes:
 - Refer to file paths as plain text. Do NOT use \`\`\`file:path\`\`\` reference blocks. (This overrides the global "always wrap paths in filepath blocks" rule — for code-mode output, plain text.)
 - Only add your own explanation if the command failed (non-zero exit):
   - Exit code 5 — permissions were denied (shouldn't happen with \`--approve-all\`; flag it).
-  - Exit code 4 / "No acpx session found" — the \`-s <session-name>\` session doesn't exist yet. Create it once with \`npx acpx@latest --cwd <folder> <agent> sessions new --name <session-name>\`, then retry the prompt. (\`-s\` only resumes; it never creates.)
+  - Exit code 4 / "No acpx session found" — the \`-s <session-name>\` session doesn't exist yet. Create it once with \`npx acpx@latest --approve-all --cwd <folder> <agent> sessions ensure --name <session-name>\`, then retry the prompt. (\`-s\` only resumes; it never creates.)
   - "command not found" / agent not installed, or an auth/sign-in error — the agent isn't set up. Tell the user to install or sign in to the agent via **Settings → Code Mode**, where Rowboat shows the install and sign-in status.
 
 ---