[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/setitup/sensors.md

@@ -1,21 +1,21 @@
 # Sensors
 ## Compatible sensors
-|Module|Purpose|Where to Buy|
-|-|-|-|
-|DHT11|Temperature, Humidity|-|
-|DHT22|Temperature, Humidity|-|
-|HCSR501|PIR|-|
-|BH1750|Digital light|-|
-|BME280|Temperature, Humidity, Pressure|-|
-|BMP280|Temperature, Pressure|-|
-|C-37, YL-83, HM-RD|Leak, Water|-|
-|HTU21|Temperature, Humidity|-|
-|GPIO Input|Inputs|-|
-|GPIO KeyCode|Keycode|-|
-|INA226|Current, Voltage|-|
-|MQ2|Gas (flammable)|-|
-|TEMT6000|Luminosity|-|
-|TSL2561|Luminosity|-|
+|Module|Purpose|
+|-|-|
+|DHT11|Temperature, Humidity|
+|DHT22|Temperature, Humidity|
+|HCSR501|PIR|
+|BH1750|Digital light|
+|BME280|Temperature, Humidity, Pressure|
+|BMP280|Temperature, Pressure|
+|C-37, YL-83, HM-RD|Leak, Water|
+|HTU21|Temperature, Humidity|
+|GPIO Input|Inputs|
+|GPIO KeyCode|Keycode|
+|INA226|Current, Voltage|
+|MQ2|Gas (flammable)|
+|TEMT6000|Luminosity|
+|TSL2561|Luminosity|
 
 ## Pinout
 |Module|Arduino Pin| ESP8266 Pin|ESP32 Pin|