fix(panes): /tui works in panes with workspace instructions

Claude refused `/tui` ("Cannot switch renderers in this session — it has
restrictions a restart can't carry over") in every pane started with
--append-system-prompt-file, i.e. any workspace with instructions (member
panes usually have the owner's). The instructions are now written as the only
CLAUDE.md of a folder of their own (<data dir>/workspace-prompts/<id>/, a
member's prompt-<id>/ in the handoff dir via write-as), passed as one more
--add-dir with CLAUDE_CODE_ADDITIONAL_DIRECTORIES_CLAUDE_MD=1. Verified with
Claude Code 2.1.301: the file is listed in /memory and /tui switches. Codex
is unchanged (its pointer line names the same file).

server/lib/pty-run.js

@@ -202,7 +202,10 @@ function buildClaudeArgv({
   // `--add-dir` is VARIADIC (`<directories...>`): it swallows every following
   // argument up to the next option, so it goes first, where `--permission-mode`
   // always ends it — after the prompt it would eat the prompt as a directory.
-  if (addDirs.length) argv.push("--add-dir", ...addDirs);
+  // The instructions' own folder rides along: its CLAUDE.md is read as memory
+  // (see lane-sources.js launchExtras), so `/tui` can still restart the pane.
+  const dirs = systemPromptFile ? [...addDirs, path.dirname(systemPromptFile)] : addDirs;
+  if (dirs.length) argv.push("--add-dir", ...dirs);
   argv.push("--permission-mode", permissionMode || "auto");
   // Inside a pane Claude Code sees $TMUX and opens agent-team teammates with
   // `split-window -P -F '#{pane_id}'`. psmux ignores -F, so the id it reads
@@ -220,9 +223,6 @@ function buildClaudeArgv({
   // `=` form: `-w [name]` takes an OPTIONAL value and would otherwise swallow
   // the prompt as the worktree's name.
   if (worktreeName) argv.push(`--worktree=${worktreeName}`);
-  // From a file: the instructions can be long, and the whole argv has to fit
-  // in one tmux message. `=` form, so the path is never read as an option.
-  if (systemPromptFile) argv.push(`--append-system-prompt-file=${systemPromptFile}`);
   // Puts "bypass permissions" INTO the pane's shift+tab cycle without turning
   // it on: `claude --help` — "Enable bypassing all permission checks as an
   // option, without it being enabled by default." Without it the cycle is only
@@ -626,6 +626,11 @@ function spawnRun(args) {
     // journals and the proxy layer `-p <name>` loads live there — and the
     // tmux server's own env may predate, or never have had, CODEX_HOME.
     ...(tool === "codex" ? { CODEX_HOME: getCodexHome() } : {}),
+    // The workspace's instructions are a CLAUDE.md in an `--add-dir` folder,
+    // which Claude reads only with this set (lane-sources.js launchExtras).
+    ...(entry.launcher === "claude" && systemPromptFile
+      ? { CLAUDE_CODE_ADDITIONAL_DIRECTORIES_CLAUDE_MD: "1" }
+      : {}),
     // No CLAUDE_CODE_DISABLE_ALTERNATE_SCREEN: an inline claude duplicated its
     // output whenever the pane narrowed (tmux re-wraps the full-width rules and
     // pushes lines into history its redraw cannot clear). The user's own