refactor: fix unused imports, long lines, and type issues

Remove 35+ unused imports across 20+ files (W0611). Wrap 19 lines
to fit under 100 character limit (C0301). Add type casts and
annotations in egress_addon_core.py to resolve pyright errors
caused by JSON parsing of untyped objects.

Key changes:
- Remove unused imports (abstractmethod, mock utilities, etc)
- Split long lines at logical breaks (method calls, error messages)
- Add typing.cast() for proper type inference in JSON parsing
- Explicit type annotations for dict/list accesses

Results:
- Pylint rating: 8.73/10
- egress_addon_core.py: 0 pyright errors (was 15)
- All W0611 and C0301 issues fixed

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

bot_bottle/backend/docker/capability_apply.py

@@ -30,7 +30,6 @@ semantics open question.
 
 from __future__ import annotations
 
-import os
 import shutil
 import subprocess
 from pathlib import Path
@@ -39,7 +38,6 @@ from ...log import info, warn
 from .bottle_state import (
     mark_preserved,
     per_bottle_dockerfile,
-    per_bottle_dockerfile_path,
     transcript_snapshot_dir,
     write_per_bottle_dockerfile,
 )

bot_bottle/backend/docker/pipelock.py

@@ -15,30 +15,23 @@ import subprocess
 from pathlib import Path
 
 from ...log import die
-# Re-exported for the compose renderer + smolmachines launch step
-# (they used to import these from this module before they moved to
-# the platform-neutral pipelock module).
-from ...pipelock import (  # noqa: F401
-    PIPELOCK_CA_CERT_IN_CONTAINER,
-    PIPELOCK_CA_KEY_IN_CONTAINER,
-)
 
 
 # Pipelock image, pinned by digest. The digest is the multi-arch image
 # index for ghcr.io/luckypipewrench/pipelock:2.3.0.
 PIPELOCK_IMAGE = os.environ.get(
     "BOT_BOTTLE_PIPELOCK_IMAGE",
-    "ghcr.io/luckypipewrench/pipelock@sha256:3b1a39417b98406ddc5dc2d8fcb42865ddc0c68a43d355db55f0f8cb06bc6de9",
+    "ghcr.io/luckypipewrench/pipelock@sha256:"
+    "3b1a39417b98406ddc5dc2d8fcb42865ddc0c68a43d355db55f0f8cb06bc6de9",
 )
 
 # Listening port for pipelock's forward proxy.
 PIPELOCK_PORT = os.environ.get("BOT_BOTTLE_PIPELOCK_PORT", "8888")
 
 
-# The URL egress dials for its upstream HTTPS_PROXY. egress and
-# pipelock share the same container's network namespace inside the
-# sidecar bundle, so loopback reaches pipelock directly — no docker
-# DNS aliases involved.
+# The URL egress dials for its upstream HTTPS_PROXY. egress and pipelock
+# share the same container's network namespace inside the sidecar bundle, so
+# loopback reaches pipelock directly — no docker DNS aliases involved.
 BUNDLE_LOCAL_PIPELOCK_URL = f"http://127.0.0.1:{PIPELOCK_PORT}"