feat(agents): named and labelled agents with optional ANSI color

Chunk 1 (schema + storage): BottleSpec, ActiveAgent, and BottleMetadata
gain label and color fields. Both docker and smolmachines backends
persist them to metadata.json on prepare and surface them in
enumerate_active_agents(). AgentProvider.provision_plan() passes
label/color through to the Claude provider, which injects them into
claude.json so claude-code displays the session name and color in its
header. Codex provider accepts and ignores the knobs.

Chunk 2 (curses modal + display): cmd_start presents a two-step curses
modal — first edit the label (first keystroke replaces the pre-fill),
then optionally pick a color. cli list active renders label with ANSI
escape codes when the terminal supports it, falling back to agent_name
when no label is set.

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

bot_bottle/contrib/codex/agent_provider.py

@@ -76,8 +76,10 @@ class CodexAgentProvider(AgentProvider):
         forward_host_credentials: bool = False,
         host_env: dict[str, str] | None = None,
         trusted_project_path: str = "",
+        label: str = "",
+        color: str = "",
     ) -> AgentProvisionPlan:
-        del auth_token  # Claude-only knob
+        del auth_token, label, color  # Claude-only knobs
         resolved_guest_env = dict(guest_env or {})
         trusted_path = trusted_project_path or guest_home