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/paths.py

@@ -0,0 +1,43 @@
+"""Foundational filesystem paths for bot-bottle.
+
+`bot_bottle_root()` is the app data root — state, queue, audit logs,
+git-gate keys, and the shared DB all live under it. It defaults to
+`~/.bot-bottle` and is overridable with the **`BOT_BOTTLE_ROOT`** env var.
+
+The env override is the single knob for redirecting the root: the test
+suite points it at a throwaway dir instead of monkey-patching the function
+(every module and every flat/package copy reads the same env var, so one
+override covers them all), and operators can relocate the root if needed.
+
+This module has no bot-bottle imports, so it is safe to import from any
+layer (and to COPY flat into the sidecar bundle).
+"""
+
+from __future__ import annotations
+
+import os
+from pathlib import Path
+
+# The single shared host state DB. All bot-bottle SQLite stores (supervise
+# queue, audit, the orchestrator registry) co-tenant this one file — the
+# TableMigrations schema_key namespaces each store's tables.
+HOST_DB_FILENAME = "bot-bottle.db"
+
+
+def bot_bottle_root() -> Path:
+    """The app data root — `$BOT_BOTTLE_ROOT` if set, else `~/.bot-bottle`."""
+    override = os.environ.get("BOT_BOTTLE_ROOT")
+    return Path(override) if override else Path.home() / ".bot-bottle"
+
+
+def host_db_path() -> Path:
+    """Path to the shared host state DB, `<root>/db/bot-bottle.db`.
+
+    Kept in its own `db/` subdirectory (not directly under the root) so a
+    backend that can only bind-mount *directories* can share this one file
+    with a sidecar without exposing the root's other contents (git-gate
+    keys, per-bottle state, ...)."""
+    return bot_bottle_root() / "db" / HOST_DB_FILENAME
+
+
+__all__ = ["HOST_DB_FILENAME", "bot_bottle_root", "host_db_path"]