fix: eliminate async safety violations and migrate to pathlib (#697)

## ℹ️ Description
Eliminate all blocking I/O operations in async contexts and modernize
file path handling by migrating from os.path to pathlib.Path.

- Link to the related issue(s): #692 
- Get rid of the TODO in pyproject.toml
- The added debug logging will ease the troubleshooting for path related
issues.

## 📋 Changes Summary

- Enable ASYNC210, ASYNC230, ASYNC240, ASYNC250 Ruff rules
- Wrap blocking urllib.request.urlopen() in run_in_executor
- Wrap blocking file operations (open, write) in run_in_executor
- Replace blocking os.path calls with async helpers using
run_in_executor
- Replace blocking input() with await ainput()
- Migrate extract.py from os.path to pathlib.Path
- Use Path() constructor and / operator for path joining
- Use Path.mkdir(), Path.rename() in executor instead of os functions
- Create mockable _path_exists() and _path_is_dir() helpers
- Add debug logging for all file system operations

### ⚙️ Type of Change
Select the type(s) of change(s) included in this pull request:
- [X] 🐞 Bug fix (non-breaking change which fixes an issue)
- [ ] ✨ New feature (adds new functionality without breaking existing
usage)
- [ ] 💥 Breaking change (changes that might break existing user setups,
scripts, or configurations)


## ✅ Checklist
Before requesting a review, confirm the following:
- [X] I have reviewed my changes to ensure they meet the project's
standards.
- [X] I have tested my changes and ensured that all tests pass (`pdm run
test`).
- [X] I have formatted the code (`pdm run format`).
- [X] I have verified that linting passes (`pdm run lint`).
- [X] I have updated documentation where necessary.

By submitting this pull request, I confirm that you can use, modify,
copy, and redistribute this contribution, under the terms of your
choice.


<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **Refactor**
  * Made user prompt non‑blocking to improve responsiveness.
* Converted filesystem/path handling and prefs I/O to async‑friendly
operations; moved blocking network and file work to background tasks.
* Added async file/path helpers and async port‑check before browser
connections.

* **Tests**
* Expanded unit tests for path helpers, image download success/failure,
prefs writing, and directory creation/renaming workflows.

<sub>✏️ Tip: You can customize this high-level summary in your review
settings.</sub>
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

src/kleinanzeigen_bot/utils/files.py

@@ -1,7 +1,8 @@
 # SPDX-FileCopyrightText: © Sebastian Thomschke and contributors
 # SPDX-License-Identifier: AGPL-3.0-or-later
 # SPDX-ArtifactOfProjectHomePage: https://github.com/Second-Hand-Friends/kleinanzeigen-bot/
-import os
+import asyncio, os  # isort: skip
+from pathlib import Path
 
 
 def abspath(relative_path:str, relative_to:str | None = None) -> str:
@@ -24,3 +25,23 @@ def abspath(relative_path:str, relative_to:str | None = None) -> str:
         base = os.path.dirname(base)
 
     return os.path.normpath(os.path.join(base, relative_path))
+
+
+async def exists(path:str | Path) -> bool:
+    """
+    Asynchronously check if a file or directory exists.
+
+    :param path: Path to check
+    :return: True if path exists, False otherwise
+    """
+    return await asyncio.get_running_loop().run_in_executor(None, Path(path).exists)
+
+
+async def is_dir(path:str | Path) -> bool:
+    """
+    Asynchronously check if a path is a directory.
+
+    :param path: Path to check
+    :return: True if path is a directory, False otherwise
+    """
+    return await asyncio.get_running_loop().run_in_executor(None, Path(path).is_dir)

src/kleinanzeigen_bot/utils/web_scraping_mixin.py

@@ -22,7 +22,7 @@ from nodriver.core.tab import Tab as Page
 from kleinanzeigen_bot.model.config_model import Config as BotConfig
 from kleinanzeigen_bot.model.config_model import TimeoutConfig
 
-from . import loggers, net
+from . import files, loggers, net
 from .chrome_version_detector import (
     ChromeVersionInfo,
     detect_chrome_version_from_binary,
@@ -100,6 +100,37 @@ class BrowserConfig:
         self.profile_name:str | None = None
 
 
+def _write_initial_prefs(prefs_file:str) -> None:
+    with open(prefs_file, "w", encoding = "UTF-8") as fd:
+        json.dump({
+            "credentials_enable_service": False,
+            "enable_do_not_track": True,
+            "google": {
+                "services": {
+                    "consented_to_sync": False
+                }
+            },
+            "profile": {
+                "default_content_setting_values": {
+                    "popups": 0,
+                    "notifications": 2  # 1 = allow, 2 = block browser notifications
+                },
+                "password_manager_enabled": False
+            },
+            "signin": {
+                "allowed": False
+            },
+            "translate_site_blacklist": [
+                "www.kleinanzeigen.de"
+            ],
+            "devtools": {
+                "preferences": {
+                    "currentDockState": '"bottom"'
+                }
+            }
+        }, fd)
+
+
 class WebScrapingMixin:
 
     def __init__(self) -> None:
@@ -174,7 +205,7 @@ class WebScrapingMixin:
         LOG.info("Creating Browser session...")
 
         if self.browser_config.binary_location:
-            ensure(os.path.exists(self.browser_config.binary_location), f"Specified browser binary [{self.browser_config.binary_location}] does not exist.")
+            ensure(await files.exists(self.browser_config.binary_location), f"Specified browser binary [{self.browser_config.binary_location}] does not exist.")
         else:
             self.browser_config.binary_location = self.get_compatible_browser()
         LOG.info(" -> Browser binary location: %s", self.browser_config.binary_location)
@@ -289,41 +320,14 @@ class WebScrapingMixin:
             profile_dir = os.path.join(cfg.user_data_dir, self.browser_config.profile_name or "Default")
             os.makedirs(profile_dir, exist_ok = True)
             prefs_file = os.path.join(profile_dir, "Preferences")
-            if not os.path.exists(prefs_file):
+            if not await files.exists(prefs_file):
                 LOG.info(" -> Setting chrome prefs [%s]...", prefs_file)
-                with open(prefs_file, "w", encoding = "UTF-8") as fd:
-                    json.dump({
-                        "credentials_enable_service": False,
-                        "enable_do_not_track": True,
-                        "google": {
-                            "services": {
-                                "consented_to_sync": False
-                            }
-                        },
-                        "profile": {
-                            "default_content_setting_values": {
-                                "popups": 0,
-                                "notifications": 2  # 1 = allow, 2 = block browser notifications
-                            },
-                            "password_manager_enabled": False
-                        },
-                        "signin": {
-                            "allowed": False
-                        },
-                        "translate_site_blacklist": [
-                            "www.kleinanzeigen.de"
-                        ],
-                        "devtools": {
-                            "preferences": {
-                                "currentDockState": '"bottom"'
-                            }
-                        }
-                    }, fd)
+                await asyncio.get_running_loop().run_in_executor(None, _write_initial_prefs, prefs_file)
 
         # load extensions
         for crx_extension in self.browser_config.extensions:
             LOG.info(" -> Adding Browser extension: [%s]", crx_extension)
-            ensure(os.path.exists(crx_extension), f"Configured extension-file [{crx_extension}] does not exist.")
+            ensure(await files.exists(crx_extension), f"Configured extension-file [{crx_extension}] does not exist.")
             cfg.add_extension(crx_extension)
 
         try: