feat: update check (#561)

feat(update-check): add robust update check with interval support, state management, and CLI integration

- Implement version and interval-based update checks with configurable settings
- Add CLI command `kleinanzeigen-bot update-check` for manual checks
- Introduce state file with versioning, UTC timestamps, and migration logic
- Validate and normalize intervals (1d–4w) with fallback for invalid values
- Ensure correct handling of timezones and elapsed checks
- Improve error handling, logging, and internationalization (i18n)
- Add comprehensive test coverage for config, interval logic, migration, and CLI
- Align default config, translations, and schema with new functionality
- Improve help command UX by avoiding config/log loading for `--help`
- Update documentation and README with full feature overview

pdm.lock

@@ -5,7 +5,7 @@
 groups = ["default", "dev"]
 strategy = ["inherit_metadata"]
 lock_version = "4.5.0"
-content_hash = "sha256:4c861bebeac9e92661923a7e8d04a695c2185a5d0f85179fb858febd2503fdaf"
+content_hash = "sha256:25eeef987c3fa08a52036fd696587f2fb89c6474225d7c9108e5d0281aa54d26"
 
 [[metadata.targets]]
 requires_python = ">=3.10,<3.14"
@@ -1147,6 +1147,20 @@ files = [
     {file = "pytest_cov-6.2.1.tar.gz", hash = "sha256:25cc6cc0a5358204b8108ecedc51a9b57b34cc6b8c967cc2c01a4e00d8a67da2"},
 ]
 
+[[package]]
+name = "pytest-mock"
+version = "3.14.0"
+requires_python = ">=3.8"
+summary = "Thin-wrapper around the mock package for easier use with pytest"
+groups = ["dev"]
+dependencies = [
+    "pytest>=6.2.5",
+]
+files = [
+    {file = "pytest-mock-3.14.0.tar.gz", hash = "sha256:2719255a1efeceadbc056d6bf3df3d1c5015530fb40cf347c0f9afac88410bd0"},
+    {file = "pytest_mock-3.14.0-py3-none-any.whl", hash = "sha256:0b72c38033392a5f4621342fe11e9219ac11ec9d375f8e2a0c164539e0d70f6f"},
+]
+
 [[package]]
 name = "pytest-rerunfailures"
 version = "15.1"
@@ -1384,6 +1398,20 @@ files = [
     {file = "tomli-2.2.1.tar.gz", hash = "sha256:cd45e1dc79c835ce60f7404ec8119f2eb06d38b1deba146f07ced3bbc44505ff"},
 ]
 
+[[package]]
+name = "types-requests"
+version = "2.32.0.20250515"
+requires_python = ">=3.9"
+summary = "Typing stubs for requests"
+groups = ["dev"]
+dependencies = [
+    "urllib3>=2",
+]
+files = [
+    {file = "types_requests-2.32.0.20250515-py3-none-any.whl", hash = "sha256:f8eba93b3a892beee32643ff836993f15a785816acca21ea0ffa006f05ef0fb2"},
+    {file = "types_requests-2.32.0.20250515.tar.gz", hash = "sha256:09c8b63c11318cb2460813871aaa48b671002e59fda67ca909e9883777787581"},
+]
+
 [[package]]
 name = "typing-extensions"
 version = "4.14.0"