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/backend/docker/cleanup.py

@@ -26,7 +26,7 @@ from __future__ import annotations
 import shutil
 import subprocess
 
-from ... import supervise as _supervise
+from ...paths import bot_bottle_root
 from ...log import info, warn
 from . import util as docker_mod
 from .bottle_cleanup_plan import DockerBottleCleanupPlan
@@ -94,7 +94,7 @@ def _list_orphan_state_dirs(
     ANY backend — used so this docker-side check doesn't reap a
     running non-docker bottle's state dir (the layout is shared
     across backends)."""
-    state_root = _supervise.bot_bottle_root() / "state"
+    state_root = bot_bottle_root() / "state"
     if not state_root.is_dir():
         return []
     orphans: list[str] = []