feature/hls: Add HLS playback support, and refactors documentation for better usability and maintainability. (#1)

## Overview
This PR introduces HLS playback support, improves the player experience, and refactors documentation for better usability and maintainability.

## Key Features

### HLS Playback Support
- Add HLS integration via new JavaScript assets:
  - `hls.min.js`
  - `plyr.hls.start.js`
  - `watch.hls.js`
- Separate DASH and HLS logic:
  - `plyr-start.js` → `plyr.dash.start.js`
  - `watch.js` → `watch.dash.js`
- Update templates (`embed.html`, `watch.html`) for conditional player loading

### Native Storyboard Preview
- Add `native_player_storyboard` setting in `settings.py`
- Implement hover thumbnail preview for native player modes
- Add `storyboard-preview.js`

### UI and Player Adjustments
- Update templates and styles (`custom_plyr.css`)
- Modify backend modules to support new player modes:
  - `watch.py`, `channel.py`, `util.py`, and related components

### Internationalization
- Update translation files:
  - `messages.po`
  - `messages.pot`

### Testing and CI
- Add and update tests:
  - `test_shorts.py`
  - `test_util.py`
- Minor CI and release script improvements

## Documentation

### OpenRC Service Guide Rewrite
- Restructure `docs/basic-script-openrc/README.md` into:
  - Prerequisites
  - Installation
  - Service Management
  - Verification
  - Troubleshooting
- Add admonition blocks:
  - `[!NOTE]`, `[!TIP]`, `[!IMPORTANT]`, `[!WARNING]`, `[!CAUTION]`
- Fix log inspection command:
  ```bash
  doas tail -f /var/log/ytlocal.log
  ````

* Add path placeholders and clarify permission requirements
* Remove legacy and duplicate content

Reviewed-on: #1
Co-authored-by: Astounds <kirito@disroot.org>
Co-committed-by: Astounds <kirito@disroot.org>

youtube/get_app_version/__init__.py

@@ -1 +1,3 @@
-from .get_app_version import *
+from .get_app_version import app_version
+
+__all__ = ['app_version']

youtube/get_app_version/get_app_version.py

@@ -1,47 +1,56 @@
 from __future__ import unicode_literals
-from subprocess import (
-    call,
-    STDOUT
-)
-from ..version import __version__
 import os
+import shutil
 import subprocess
 
+from ..version import __version__
+
 
 def app_version():
     def minimal_env_cmd(cmd):
         # make minimal environment
         env = {k: os.environ[k] for k in ['SYSTEMROOT', 'PATH'] if k in os.environ}
         env.update({'LANGUAGE': 'C', 'LANG': 'C', 'LC_ALL': 'C'})
-
         out = subprocess.Popen(cmd, stdout=subprocess.PIPE, env=env).communicate()[0]
         return out
 
     subst_list = {
-        "version": __version__,
-        "branch": None,
-        "commit": None
+        'version': __version__,
+        'branch': None,
+        'commit': None,
     }
 
-    if os.system("command -v git > /dev/null 2>&1") != 0:
+    # Use shutil.which instead of `command -v`/os.system so we don't spawn a
+    # shell (CWE-78 hardening) and so it works cross-platform.
+    if shutil.which('git') is None:
         return subst_list
 
-    if call(["git", "branch"], stderr=STDOUT, stdout=open(os.devnull, 'w')) != 0:
+    try:
+        # Check we are inside a git work tree. Using DEVNULL avoids the
+        # file-handle leak from `open(os.devnull, 'w')`.
+        rc = subprocess.call(
+            ['git', 'branch'],
+            stderr=subprocess.DEVNULL,
+            stdout=subprocess.DEVNULL,
+        )
+    except OSError:
+        return subst_list
+    if rc != 0:
         return subst_list
 
-    describe = minimal_env_cmd(["git", "describe", "--tags", "--always"])
+    describe = minimal_env_cmd(['git', 'describe', '--tags', '--always'])
     git_revision = describe.strip().decode('ascii')
 
-    branch = minimal_env_cmd(["git", "branch"])
+    branch = minimal_env_cmd(['git', 'branch'])
     git_branch = branch.strip().decode('ascii').replace('* ', '')
 
     subst_list.update({
-        "branch": git_branch,
-        "commit": git_revision
+        'branch': git_branch,
+        'commit': git_revision,
     })
 
     return subst_list
 
 
-if __name__ == "__main__":
+if __name__ == '__main__':
     app_version()