feat(run): make bypass permissions selectable in a lane pane's shift+tab cycle

`claude` only offers bypass in its shift+tab permission cycle when started
with `--allow-dangerously-skip-permissions`, which the pane argv never passed.
A dashboard-started run was therefore stuck cycling plan/auto/manual/
accept-edits, while the same session attached from a real terminal could
reach bypass.

The flag makes bypass SELECTABLE, not enabled — `claude --help`: "Enable
bypassing all permission checks as an option, without it being enabled by
default." The starting mode is still whatever `--permission-mode` says
(`acceptEdits` by default) and `--dangerously-skip-permissions`, which would
actually turn it on, is still never passed. Entering bypass remains an
explicit human shift+tab in the pane, or an explicit
`permissionMode: "bypassPermissions"` on POST /api/run.

server/__tests__/pty-run.test.js

@@ -116,6 +116,26 @@ describe("pty-run", () => {
     assert.ok(newSessionArgv.includes("abc12345"));
   });
 
+  it("spawnRun offers bypass in the pane's shift+tab cycle without starting in it", () => {
+    let newSessionArgv = null;
+    tmux.__setExecImpl((args) => {
+      if (args[0] === "has-session") {
+        const e = new Error("gone");
+        e.status = 1;
+        throw e;
+      }
+      if (args[0] === "new-session") newSessionArgv = args;
+      return "";
+    });
+    pty.spawnRun({ laneId: 4, cwd: "/tmp/repo" });
+    assert.ok(newSessionArgv.includes("--allow-dangerously-skip-permissions"));
+    // ...as an OPTION only: the starting mode stays the requested one, and
+    // `--dangerously-skip-permissions` (which would enable it) is never passed.
+    assert.ok(!newSessionArgv.includes("--dangerously-skip-permissions"));
+    const modeAt = newSessionArgv.indexOf("--permission-mode");
+    assert.equal(newSessionArgv[modeAt + 1], "acceptEdits");
+  });
+
   it("spawnRun appends a positional initial prompt after argv flags", () => {
     let newSessionArgv = null;
     tmux.__setExecImpl((args) => {

server/lib/pty-run.js

@@ -62,6 +62,13 @@ function makeErr(code, message) {
 function buildArgv({ model, permissionMode, effort, resumeSessionId, initialPrompt }) {
   const argv = ["claude"];
   argv.push("--permission-mode", permissionMode || "acceptEdits");
+  // 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
+  // plan/auto/manual/acceptEdits, so a run started in any non-bypass mode could
+  // never reach bypass from inside the pane, while a real terminal could.
+  // The starting mode is still whatever --permission-mode says above.
+  argv.push("--allow-dangerously-skip-permissions");
   if (model) argv.push("--model", model);
   if (effort && EFFORT_LEVELS.has(effort)) argv.push("--effort", effort);
   if (resumeSessionId) argv.push("--resume", resumeSessionId);