Improve Bluesky reply/quote accessibility and split test bootstrap workflow

- Fix Bluesky quoted post rendering across list output, screen-reader speech, and View Post by centralizing quote extraction.
- Add robust quote URL extraction (facets/embed/text), include quoted URLs in URL shortcuts, and append full quoted URLs when hidden/truncated.
- Improve reply context handling:
  - add and use `$reply_to` template variable,
  - hydrate missing reply target handles in home/feed items,
  - keep backward compatibility for templates that do not include `$reply_to`.
- Align Bluesky default/fallback post templates to include reply context (`$reply_to`).
- Add/extend focused Bluesky tests for quote text, quote URLs, reply context, and template fallback behavior.
- Refactor scripts:
  - add bootstrap-dev.ps1 for environment setup (submodules, venv, deps),
  - keep run-tests.ps1 focused on running tests only,
  - add PowerShell comment-based help in English.
- Update README with the new bootstrap/test workflow and examples.

src/blueski.defaults

@@ -44,7 +44,7 @@ braille_reporting = boolean(default=True)
 speech_reporting = boolean(default=True)
 
 [templates]
-post = string(default="$display_name, $safe_text $date.")
+post = string(default="$display_name, $reply_to$safe_text $date.")
 person = string(default="$display_name (@$screen_name). $followers followers, $following following, $posts posts. Joined $created_at.")
 notification = string(default="$display_name $text, $date")