fix(terminal): start PTY before viewport mounts without dropping output or startup replies

Terminal creation no longer waits for the Ghostty viewport to report its
size: it starts the PTY immediately with a container/font-derived
provisional size (falling back to 80x24), then resizes once the real
viewport dimensions are known, with a dedupe guard while sizing settles.

Starting the shell earlier means it can emit device/theme queries before
a browser terminal is attached to answer them, so the server now answers
primary device attribute queries itself (Fish blocks ~10s on this at
startup) and bun-pty buffers output emitted before a data subscriber
attaches. Also fixes a few WebSocket transport reconnect races surfaced
by session creation now overlapping renderer setup.

package.json

@@ -178,6 +178,7 @@
     "vite": "^7.1.2"
   },
   "patchedDependencies": {
-    "@tanstack/virtual-core@3.17.3": "bun-patches/@tanstack+virtual-core+3.17.3.patch"
+    "@tanstack/virtual-core@3.17.3": "bun-patches/@tanstack+virtual-core+3.17.3.patch",
+    "bun-pty@0.4.8": "bun-patches/bun-pty@0.4.8.patch"
   }
 }