extend process spawn to allow allocating a tty, attaching (#96)

using the same approach that `docker exec ...` uses:
- allow for allocating a tty when making a process
- expose an http endpoint that is hijack-able to do pure tcp stuff
 
`./cmd/shell` contains a proof of concept for what would eventually land
in the `kernel` CLI.

demo running against the image running in unikraft:

https://screen.studio/share/6imUEYCv




<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> Implements interactive PTY support for spawned processes and an
attach/resize workflow, plus a small CLI demo and minor wrapper tweaks.
> 
> - Extends `ProcessSpawnRequest` with `allocate_tty`, `rows`, `cols`;
server spawns PTY-backed cmds via `creack/pty`, tracks `ptyFile/isTTY`,
and defers pipe readers in PTY mode
> - Adds raw attach endpoint `GET /process/{process_id}/attach` (HTTP
hijack) and `POST /process/{process_id}/resize`; enforces single active
attach and uses poll-based PTY→conn copy; cleans up FDs and retains
process status briefly post-exit
> - Updates OpenAPI (`openapi.yaml`) and generated client/server
(`lib/oapi`) to include PTY fields and `processResize`; adds deps
`creack/pty`, `x/sys`, `x/term`
> - New `cmd/shell` PoC: spawns `/bin/bash` with TTY, hijacks attach
over TCP/TLS, resizes on `SIGWINCH`
> - Wrapper scripts: ensure/export a sane `HOSTNAME` early in
headful/headless images
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
7d47214. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

---------

Co-authored-by: Sayan <[email protected]>

Author: rgarcia

images/chromium-headful/wrapper.sh

@@ -33,6 +33,22 @@ if [[ -z "${WITHDOCKER:-}" ]]; then
   disable_scale_to_zero
 fi
 
+# -----------------------------------------------------------------------------
+# Ensure a sensible hostname ---------------------------------------------------
+# -----------------------------------------------------------------------------
+# Some environments boot with an empty or \"(none)\" hostname which shows up in
+# prompts. Best-effort set a friendly hostname early so services inherit it.
+if h=$(cat /proc/sys/kernel/hostname 2>/dev/null); then
+  if [ -z "$h" ] || [ "$h" = "(none)" ]; then
+    if command -v hostname >/dev/null 2>&1; then
+      hostname kernel-vm 2>/dev/null || true
+    fi
+    echo -n "kernel-vm" > /proc/sys/kernel/hostname 2>/dev/null || true
+  fi
+fi
+# Also export HOSTNAME so shells pick it up immediately.
+export HOSTNAME="${HOSTNAME:-kernel-vm}"
+
 # -----------------------------------------------------------------------------
 # House-keeping for the unprivileged "kernel" user --------------------------------
 # Some Chromium subsystems want to create files under $HOME (NSS cert DB, dconf

images/chromium-headless/image/wrapper.sh

@@ -30,6 +30,19 @@ if [[ -z "${WITHDOCKER:-}" ]]; then
   disable_scale_to_zero
 fi
 
+# -----------------------------------------------------------------------------
+# Ensure a sensible hostname ---------------------------------------------------
+# -----------------------------------------------------------------------------
+if h=$(cat /proc/sys/kernel/hostname 2>/dev/null); then
+  if [ -z "$h" ] || [ "$h" = "(none)" ]; then
+    if command -v hostname >/dev/null 2>&1; then
+      hostname kernel-vm 2>/dev/null || true
+    fi
+    echo -n "kernel-vm" > /proc/sys/kernel/hostname 2>/dev/null || true
+  fi
+fi
+export HOSTNAME="${HOSTNAME:-kernel-vm}"
+
 # if CHROMIUM_FLAGS is not set, default to the flags used in playwright_stealth
 if [ -z "${CHROMIUM_FLAGS:-}" ]; then
   CHROMIUM_FLAGS="--accept-lang=en-US,en \