fix(smolmachines): consolidate virtiofs mounts to stay within libkrun limit

libkrun limits total mounts + port-mappings to 5. With all three
sidecar daemons active (egress, git-gate, supervise), the prior
layout used 3 mounts + 3 ports = 6, causing the VM to crash at boot
with krun_start_enter returned -22.

Merge the egress confdir and git-gate scripts into a single staging
directory mounted at /bot-bottle-data/ with egress/ and git-gate/
subdirectories, reducing to 2 mounts + 3 ports = 5. Also clean up
leftover VMs before creating new ones to handle interrupted teardowns.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

tests/unit/test_smolmachines_provision.py

@@ -405,8 +405,8 @@ class TestBundleLaunchSpec(unittest.TestCase):
         )
 
         with patch(
-            "bot_bottle.backend.smolmachines.launch._stage_git_gate_for_smolvm",
-            return_value=(Path("/tmp/smolvm-scripts"), Path("/tmp/smolvm-creds")),
+            "bot_bottle.backend.smolmachines.launch._stage_sidecar_data",
+            return_value=Path("/tmp/smolvm-sidecar-data"),
         ):
             spec = _bundle_launch_spec(plan, "net", "127.0.0.16")
 
@@ -420,7 +420,11 @@ class TestBundleLaunchSpec(unittest.TestCase):
     def test_canary_env_registered_as_sensitive_in_bundle(self):
         plan = _plan(canary=True)
 
-        spec = _bundle_launch_spec(plan, "net", "127.0.0.16")
+        with patch(
+            "bot_bottle.backend.smolmachines.launch._stage_sidecar_data",
+            return_value=Path("/tmp/smolvm-sidecar-data"),
+        ):
+            spec = _bundle_launch_spec(plan, "net", "127.0.0.16")
 
         self.assertIn("CANON_ALPHA_SECRET=fake-canary-value", spec.environment)
         self.assertIn(
@@ -431,7 +435,11 @@ class TestBundleLaunchSpec(unittest.TestCase):
     def test_supervise_adds_daemon_volume_and_env(self):
         from bot_bottle.supervise import DB_PATH_IN_CONTAINER
         plan = _plan(supervise=True)
-        spec = _bundle_launch_spec(plan, "net", "127.0.0.16")
+        with patch(
+            "bot_bottle.backend.smolmachines.launch._stage_sidecar_data",
+            return_value=Path("/tmp/smolvm-sidecar-data"),
+        ):
+            spec = _bundle_launch_spec(plan, "net", "127.0.0.16")
         self.assertIn("supervise", spec.daemons_csv)
         self.assertIn(f"SUPERVISE_DB_PATH={DB_PATH_IN_CONTAINER}", spec.environment)
         # virtiofs requires directory mounts; the DB's parent dir is
@@ -562,8 +570,8 @@ class TestLaunchResourceWiring(unittest.TestCase):
             "bot_bottle.backend.smolmachines.launch._bundle.start_bundle_vm",
             return_value=raw_launch,
         ) as start_vm, patch(
-            "bot_bottle.backend.smolmachines.launch._stage_git_gate_for_smolvm",
-            return_value=(Path("/tmp/smolvm-scripts"), Path("/tmp/smolvm-creds")),
+            "bot_bottle.backend.smolmachines.launch._stage_sidecar_data",
+            return_value=Path("/tmp/smolvm-sidecar-data"),
         ), patch(
             "bot_bottle.backend.smolmachines.launch._forward.start_forwarder",
             return_value=handle,