fix: thread slug + resolved_env from prepare to each backend's _resolve_plan

BottleBackend.prepare computed slug and resolved_env but never passed
them to _resolve_plan. The concrete docker/smolmachines _resolve_plan
methods still had the old (spec, *, stage_dir) signature too, so
prepare's kwargs blew up with "unexpected keyword argument
'instance_name'" the moment cli.py start was invoked.

Update the abstract _resolve_plan signature and both backend
implementations to accept the full kwarg set prepare passes, and
forward to resolve_plan.resolve_plan() with everything.

bot_bottle/backend/__init__.py

@@ -323,6 +323,8 @@ class BottleBackend(ABC, Generic[PlanT, CleanupT]):
 
         return self._resolve_plan(
             spec,
+            slug=slug,
+            resolved_env=resolved_env,
             instance_name=instance_name, # FIXME: move to agent provision plan
             agent_image=agent_image, # FIXME: move to agent provision plan
             prompt_file=prompt_file, # FIXME: move to agent provision plan
@@ -331,7 +333,7 @@ class BottleBackend(ABC, Generic[PlanT, CleanupT]):
             egress_plan=egress_plan,
             supervise_plan=supervise_plan,
             git_gate_plan=git_gate_plan,
-            stage_dir=stage_dir
+            stage_dir=stage_dir,
         )
 
     def _build_guest_env(self, resolved_env: ResolvedEnv) -> dict[str, str]:
@@ -395,6 +397,9 @@ class BottleBackend(ABC, Generic[PlanT, CleanupT]):
     @abstractmethod
     def _resolve_plan(self,
                       spec: BottleSpec,
+                      *,
+                      slug: str,
+                      resolved_env: ResolvedEnv,
                       instance_name: str,
                       agent_image: str,
                       prompt_file: Path,

bot_bottle/backend/docker/backend.py

@@ -48,8 +48,36 @@ class DockerBottleBackend(BottleBackend["DockerBottlePlan", "DockerBottleCleanup
         launch."""
         return shutil.which("docker") is not None
 
-    def _resolve_plan(self, spec: BottleSpec, *, stage_dir: Path) -> DockerBottlePlan:
-        return _resolve_plan.resolve_plan(spec, stage_dir=stage_dir)
+    def _resolve_plan(
+        self,
+        spec: BottleSpec,
+        *,
+        slug: str,
+        resolved_env,
+        instance_name: str,
+        agent_image: str,
+        prompt_file: Path,
+        agent_provision_plan,
+        agent_dockerfile_path: str,
+        egress_plan,
+        git_gate_plan,
+        supervise_plan,
+        stage_dir: Path,
+    ) -> DockerBottlePlan:
+        return _resolve_plan.resolve_plan(
+            spec,
+            slug=slug,
+            resolved_env=resolved_env,
+            instance_name=instance_name,
+            agent_image=agent_image,
+            agent_dockerfile_path=agent_dockerfile_path,
+            prompt_file=prompt_file,
+            agent_provision_plan=agent_provision_plan,
+            egress_plan=egress_plan,
+            supervise_plan=supervise_plan,
+            git_gate_plan=git_gate_plan,
+            stage_dir=stage_dir,
+        )
 
     @contextmanager
     def launch(self, plan: DockerBottlePlan) -> Generator[DockerBottle, None, None]:

bot_bottle/backend/smolmachines/backend.py

@@ -42,9 +42,35 @@ class SmolmachinesBottleBackend(
         return _smolvm.is_available()
 
     def _resolve_plan(
-        self, spec: BottleSpec, *, stage_dir: Path
+        self,
+        spec: BottleSpec,
+        *,
+        slug: str,
+        resolved_env,
+        instance_name: str,
+        agent_image: str,
+        prompt_file: Path,
+        agent_provision_plan,
+        agent_dockerfile_path: str,
+        egress_plan,
+        git_gate_plan,
+        supervise_plan,
+        stage_dir: Path,
     ) -> SmolmachinesBottlePlan:
-        return _resolve_plan.resolve_plan(spec, stage_dir=stage_dir)
+        return _resolve_plan.resolve_plan(
+            spec,
+            slug=slug,
+            resolved_env=resolved_env,
+            instance_name=instance_name,
+            agent_image=agent_image,
+            agent_dockerfile_path=agent_dockerfile_path,
+            prompt_file=prompt_file,
+            agent_provision_plan=agent_provision_plan,
+            egress_plan=egress_plan,
+            supervise_plan=supervise_plan,
+            git_gate_plan=git_gate_plan,
+            stage_dir=stage_dir,
+        )
 
     @contextmanager
     def launch(