refactor: drop the vestigial bot_bottle_root/host_db_path re-exports (#352)

paths is the single home now, so stop re-exporting the path helpers from
supervise: remove host_db_path from supervise's imports + __all__ (it was
re-export-only) and drop bot_bottle_root from __all__ (kept as an import,
still used by audit_dir). supervise_types was already clean. Repoint the
last readers (test_supervise imports host_db_path from paths;
test_supervise_edge calls paths.bot_bottle_root) and refresh the doc
mentions. No supervise.bot_bottle_root / supervise.host_db_path references
remain.

Behavior-preserving: full unit suite unchanged (only the pre-existing
/bin/sleep sidecar-init errors).

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

tests/unit/test_supervise_edge.py

@@ -12,6 +12,7 @@ from unittest.mock import patch
 
 from bot_bottle import supervise
 from bot_bottle.audit_store import AuditStore
+from bot_bottle.paths import bot_bottle_root
 from bot_bottle.queue_store import QueueStore
 from bot_bottle.supervise import (
     AuditEntry,
@@ -39,7 +40,7 @@ def _proposal() -> Proposal:
 
 class TestPathHelpers(unittest.TestCase):
     def test_bot_bottle_root(self) -> None:
-        self.assertTrue(str(supervise.bot_bottle_root()).endswith(".bot-bottle"))
+        self.assertTrue(str(bot_bottle_root()).endswith(".bot-bottle"))
 
 
 class TestReadMalformed(unittest.TestCase):