fix(tmux,run,hooks): the four pre-existing bugs the #37 evaluation found

- tmux targets are exact (`=name`, `=name:` for panes/options): a bare
  `-t agenthub-lane-1` resolves by prefix to agenthub-lane-12 once lane 1
  is gone, so killing a finished lane could kill another.
- getRun/killRun refuse ids that are not `agenthub-lane-<n>`, so
  DELETE /api/run/main can no longer kill a user's own tmux session.
- router/apply reports restart_required only for a running pane; getRun
  returns a `gone` handle, so it was always true.
- needs_action is cleared only by the session that raised it (new nullable
  lanes.needs_action_session); a second session in the same cwd used to
  clear it on its second hook.

server/lib/tmux.js

@@ -33,9 +33,16 @@ function __reset() {
   execImpl = (args) => execFileSync("tmux", args, EXEC_OPTS);
 }
 
+// tmux resolves a bare `-t agenthub-lane-1` by PREFIX when no exact match
+// exists, so it would hit `agenthub-lane-12` once lane 1's session is gone —
+// and killSession would kill the wrong lane. `=` forces an exact match; pane
+// and option targets need the trailing `:` (tmux 3.4 rejects `=name` there).
+const session = (name) => `=${name}`;
+const pane = (name) => `=${name}:`;
+
 function hasSession(name) {
   try {
-    execImpl(["has-session", "-t", name]);
+    execImpl(["has-session", "-t", session(name)]);
     return true;
   } catch {
     return false;
@@ -71,7 +78,7 @@ function newSession({ name, cwd, argv, env }) {
 // this option existed — or before a server restart picked up the change —
 // still gets it; `set-option` is idempotent, so re-running it is harmless.
 function enableMouse(name) {
-  execImpl(["set-option", "-t", name, "mouse", "on"]);
+  execImpl(["set-option", "-t", pane(name), "mouse", "on"]);
 }
 
 /**
@@ -82,7 +89,8 @@ function enableMouse(name) {
 function paneCommand(name) {
   try {
     return (
-      execImpl(["display-message", "-p", "-t", name, "#{pane_current_command}"]).trim() || null
+      execImpl(["display-message", "-p", "-t", pane(name), "#{pane_current_command}"]).trim() ||
+      null
     );
   } catch {
     return null;
@@ -107,7 +115,7 @@ function sendCommand(name, argv, env, cwd) {
     "respawn-pane",
     "-k",
     "-t",
-    name,
+    pane(name),
     ...(cwd ? ["-c", cwd] : []),
     ...envFlags(env),
     "--",
@@ -125,14 +133,14 @@ function sendCommand(name, argv, env, cwd) {
  * only the first line and leave the rest sitting unsent in the input box.
  */
 function sendText(name, text) {
-  execImpl(["send-keys", "-t", name, "-l", text]);
-  execImpl(["send-keys", "-t", name, "Enter"]);
+  execImpl(["send-keys", "-t", pane(name), "-l", text]);
+  execImpl(["send-keys", "-t", pane(name), "Enter"]);
 }
 
 /** Idempotent — a session that's already gone is not an error. */
 function killSession(name) {
   try {
-    execImpl(["kill-session", "-t", name]);
+    execImpl(["kill-session", "-t", session(name)]);
   } catch {
     /* already gone */
   }