Thunder Mountain Radio — full action/button audit fix pass

Base used:
- ThunderMountainRadio_dj_fan_background_divider_fix_2026-03-24.zip

This pass corrected:
- Restored the good divider height and changed the new divider image to fit inside the strip instead of oversizing/cropping it.
- Updated admin divider styling to match the public Thunder divider artwork and sizing.
- Kept the footer on live listeners/visitors online only. No old lifetime page counter display was added in this pass.
- Reworked admin delete/clear flows to use POST + stable keys instead of fragile GET index deletes.
- Fixed admin Contact messages clear/delete.
- Fixed admin Requests clear/delete/approve/unapprove/mark played.
- Fixed admin Comments clear/delete/approve/unapprove/ban handling.
- Fixed admin Join applications clear/delete.
- Ignored blank template records in requests/applications so empty ghost entries no longer show.
- Tightened homepage comments so admin comments toggle is respected.
- Fixed public/admin chat API path handling for local/test installs and cleaned chat API handlers.

Files changed:
- assets/css/style.css
- admin/assets/admin-v2.css
- admin/contact.php
- admin/requests.php
- admin/comments.php
- admin/applications.php
- index.php
- chat.php
- api/chat_get.php
- api/chat_post.php

Recommended test list:
1. Public contact submit -> admin contact delete one -> clear all.
2. Public request submit -> admin approve -> public recent approved list -> delete.
3. Homepage comment submit -> admin approve/unapprove/delete.
4. Join form submit -> admin applications delete/clear.
5. Public chat send + admin delete/clear.
6. Poll save + vote from homepage.
