fix: smoke-test agent images after build, add start --no-cache

npm treats optionalDependencies failures as non-fatal, so a transient
network blip fetching claude-code's platform-native binary during
`npm install -g` left a stub CLI in an image that still "built"
successfully — then got baked into the Docker/Container layer cache
until forced to rebuild. Post-build smoke test (provider-declared
argv, run in a throwaway container of the freshly built image) fails
the launch loudly instead of shipping a broken image; --no-cache
gives an escape hatch to force a from-scratch rebuild.

Closes #353.

bot_bottle/contrib/codex/agent_provider.py

@@ -61,6 +61,7 @@ _RUNTIME = AgentProviderRuntime(
     prompt_mode="read_prompt_file",
     bypass_args=("--dangerously-bypass-approvals-and-sandbox",),
     resume_args=("resume", "--last"),
+    smoke_test=(_CODEX_CLI, "--version"),
 )