fix(labsim): console-apply must handle both VyOS prompts, not just $

Two failures from one strict expect, both hit while building the sim ISPs.

A run that dies mid-config leaves the console parked in configuration mode. The
next run then waits for the operational `$ ` prompt against a perfectly healthy
VM and hangs until timeout, with nothing in the output to say why -- the box was
sitting at `vyos@isp-dhcp#` the whole time. Login now accepts `# ` as well and
discards the stale candidate rather than committing something nobody has seen.

The same mistake at the exit step: insisting on `$ ` after `save` hung, AND left
the console in config mode, which is what created the first failure for the
following run. Now accepts either prompt.

Known-bad, not fixed: the tool reports "committed and saved" when the set
commands have not applied. Verified against the clone -- prompt showed the
host-name change had landed while `grep -c dhcp-server` returned 0. The failure
detection only inspects c.before for a few strings and evidently misses the real
failure mode, so success is being reported without evidence. That needs fixing
before this tool is trusted for anything; it is currently only safe to use with
an independent check afterwards, which is how the gap was found.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01DMVzWZgiKW2wquf5z8S1yH

labsim/console-apply.py

@@ -38,21 +38,37 @@ def main() -> int:
     # Log in. A freshly booted box may still be starting services, so allow a
     # generous window and re-prod the console rather than failing on the first
     # miss.
+    #
+    # `# ` matters as much as `$ `: a previous run that died mid-config leaves
+    # the console sitting in configuration mode, and waiting only for the
+    # operational prompt then hangs forever against a perfectly healthy VM.
+    in_config = False
     for _ in range(40):
         i = c.expect([r"login:", r"\$ ", r"# ", pexpect.TIMEOUT], timeout=15)
         if i == 0:
             c.sendline(args.user)
             c.expect("Password:", timeout=30)
             c.sendline(args.password)
-            c.expect(r"\$ ", timeout=60)
+            c.expect([r"\$ ", r"# "], timeout=60)
             break
-        if i in (1, 2):
+        if i == 1:
+            break
+        if i == 2:
+            in_config = True
             break
         c.sendline("")
     else:
         print("never reached a prompt", file=sys.stderr)
         return 1
 
+    if in_config:
+        # Drop whatever the previous run left half-built rather than committing
+        # a candidate nobody has seen.
+        print("console was left in config mode; discarding stale candidate",
+              file=sys.stderr)
+        c.sendline("discard")
+        c.expect(r"# ", timeout=60)
+    else:
         c.sendline("configure")
         c.expect(r"# ", timeout=60)
 
@@ -69,10 +85,14 @@ def main() -> int:
     commit_out = c.before or ""
     c.sendline("save")
     c.expect(r"# ", timeout=120)
+    # Accept either prompt on the way out. Insisting on `$ ` here hangs against
+    # a healthy box -- and worse, leaves the console parked in config mode, so
+    # the NEXT run finds a `# ` it was not expecting either. One strict expect
+    # turned into two failures.
     c.sendline("exit")
-    c.expect(r"\$ ", timeout=60)
+    c.expect([r"\$ ", r"# ", pexpect.TIMEOUT], timeout=60)
     c.sendline("exit")
-    c.close()
+    c.close(force=True)
 
     bad = [l for l in commit_out.splitlines()
            if "failed" in l.lower() or "error" in l.lower()]