Improve subscription UI with large tier buttons

- Replace dropdown tier selection with attractive visual buttons
- Add tier-button CSS with hover effects and selection states
- Remove 'or pay by card' divider from subscription form for cleaner UI
- Update JavaScript to handle tier button selection events
- Fix Stripe module import conflict by renaming stripe directory to stripe_config
- Add responsive grid layout for tier buttons on mobile devices

stripe_config/.venv/lib/python3.12/site-packages/flask/signals.py

@@ -0,0 +1,17 @@
+from __future__ import annotations
+
+from blinker import Namespace
+
+# This namespace is only for signals provided by Flask itself.
+_signals = Namespace()
+
+template_rendered = _signals.signal("template-rendered")
+before_render_template = _signals.signal("before-render-template")
+request_started = _signals.signal("request-started")
+request_finished = _signals.signal("request-finished")
+request_tearing_down = _signals.signal("request-tearing-down")
+got_request_exception = _signals.signal("got-request-exception")
+appcontext_tearing_down = _signals.signal("appcontext-tearing-down")
+appcontext_pushed = _signals.signal("appcontext-pushed")
+appcontext_popped = _signals.signal("appcontext-popped")
+message_flashed = _signals.signal("message-flashed")