Document verified vacuum compatibility and fix report routing

[Lash-L]

Successful onboarding reports were missing from the tested-vacuum list, and the reporting links led to a disabled Discussions category. This consolidates the verified results into the docs and provides a working compatibility issue form.

• Record exact firmware and certificate results with links to the original reports, including the S7 Max Ultra confirmation in Onboarding Reports Overview #79. Move CurvX into the supported table and retain separate entries for distinct models and firmware versions.
• Correct the S5V firmware copied incorrectly into Onboarding Reports Overview #79. Preserve the existing RC2 confirmations for Edge 2 Set and Saros 20 Sonic; older failing reports for other firmware/variants still need retesting.
• Preserve unknown certificate issuers, firmware-specific failures, and the proxy workarounds tracked in Fix explicit HTTPS port handling for reverse proxies #77 and Device MQTT onboarding adoption fails behind a reverse proxy (client_ip correlation) #83. Document the unresolved Q7 TF+ report without claiming that V2 support fixes it.
• Replace the dead Discussions links in the templates and contributing guide with a compatibility form collecting the model, firmware, server version, certificate issuer, outcome, and workarounds.

Includes the compatibility additions proposed by Jezza34000 in #75, frazierjason in #82, and alwarnecke in #89, plus the S7 Pro Ultra report in #65 and S8+ confirmation in #66. The compatibility-only PRs #75, #82, and #89 can be closed as superseded after this merges; the broader documentation proposals in #65 and #66 still need their own disposition.

Closes #46
Closes #49
Closes #52
Closes #56
Closes #57
Closes #60
Closes #61
Closes #64
Closes #70
Closes #78
Closes #79
Closes #90

Also references #3, #47, #48, #67, and #83. Their remaining troubleshooting or device-support work is not resolved by this documentation update.