[DOCS] Overhaul new-user onboarding, home page, and upload flow (#2347)

Getting started:
- New 15-minute Getting Started guide featuring the two most popular
  tracks (BLE on esp32dev-ble, RF on lilygo-rtl_433), with broker setup
  and a verification step
- Sidebar restructured around the new-user journey; upload options
  numbered by ease; Gitpod upload method removed

Home page:
- VitePress hero with clear actions, larger hero image
- How-it-works pipeline diagram shared as a component (responsive via
  container queries), use-case grid, bigger video tiles without the
  image lightbox, refreshed press coverage list, functions pills
- Support section pointing to Theengs Bridge and
  github.com/sponsors/1technophile

Upload flow:
- Decision-oriented upload landing page (journey strip, method cards,
  comparison table)
- Pre-flight checklist and driver troubleshooting on the web installer
- Guided environment picker (bridge + hardware wizard) replacing the
  filter chips, with manifest-verified recommendations
- Post-flash next-steps card linking to the portal and verification

Board images:
- custom_img key in environments.ini and board photos for all
  web-flashable environments (licenses recorded); private prod_env.ini
  environments excluded from boards-info.json

Corrections:
- RF frequency coverage stated as 433/315/868/915MHz
- Removed references to the retired compatible.openmqttgateway.com
  site (BLE list is decoder.theengs.io), the discontinued Theengs
  Plug, and the private sponsor forum


Claude-Session: https://claude.ai/code/session_01TYysQW8tpmt1dWWuzKhTLi

Co-authored-by: Florian <1technophile@users.noreply.github.com>
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

docs/upload/troubleshoot.md

@@ -1,7 +1,7 @@
 # Troubleshooting
 
 ## Compilation/build error
-This badge [![Build Status](https://github.com/1technophile/OpenMQTTGateway/workflows/Build/badge.svg?branch=master)](https://github.com/1technophile/OpenMQTTGateway/actions?query=branch%3Amaster+workflow%3ABuild) show you the state of the compilation of the master and this one [![Build Status](https://github.com/1technophile/OpenMQTTGateway/workflows/Build/badge.svg?branch=development)](https://github.com/1technophile/OpenMQTTGateway/actions?query=branch%3Adevelopment+workflow%3ABuild) for the development branch.
+This badge [![Build Status](https://github.com/1technophile/OpenMQTTGateway/workflows/Build/badge.svg?branch=development)](https://github.com/1technophile/OpenMQTTGateway/actions?query=branch%3Adevelopment+workflow%3ABuild) show you the state of the compilation of the development branch, from which the releases are made.
 If you see a green badge this means that the code compilation is OK with the configuration given in the `docs/platformio.ini`.
 Check your environment, boards , libraries before submitting an issue or a question.