refactor: move bot_bottle_root/host_db_path to paths; kill the monkeypatch (#352)

Create bot_bottle/paths.py as the canonical home for the app-root path
helpers (bot_bottle_root, host_db_path, HOST_DB_FILENAME) — foundational,
not supervise- or db-specific. `bot_bottle_root()` now honours a
BOT_BOTTLE_ROOT env override.

Repoint every consumer (supervise, supervise_types, db_store, queue_store,
audit_store, store_manager, bottle_state, cli/supervise, docker/cleanup,
orchestrator/registry) at paths; remove the definitions (and supervise's
duplicate host_db_path) and the now-dead `import sys`. Add paths.py to the
sidecar bundle (Dockerfile.sidecars) for the flat-import copies.

Tests: replace ~12 files' monkeypatching of supervise.bot_bottle_root (and
the flat/pkg/supervise_types triple-patch dance) with a single
`use_bottle_root()` helper that sets BOT_BOTTLE_ROOT — every module and
flat/package copy reads the same env var, so one override covers them all.
Net -97 lines. Behaviour-preserving: full unit suite unchanged (only the
pre-existing /bin/sleep sidecar-init errors remain).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WBMWTEtQdJ4W5UrWuLHCck

bot_bottle/bottle_state.py

@@ -36,7 +36,7 @@ from dataclasses import dataclass
 from pathlib import Path
 from typing import cast
 
-from . import supervise as _supervise
+from .paths import bot_bottle_root
 
 
 # Directory layout: ~/.bot-bottle/state/<identity>/...
@@ -163,7 +163,7 @@ def read_metadata(identity: str) -> BottleMetadata | None:
 def bottle_state_dir(identity: str) -> Path:
     """Per-bottle state directory on the host. Created lazily by the
     write helpers; readers tolerate its absence."""
-    return _supervise.bot_bottle_root() / _STATE_SUBDIR / identity
+    return bot_bottle_root() / _STATE_SUBDIR / identity
 
 
 def per_bottle_dockerfile_path(identity: str) -> Path: