Update repository URLs to HamRadioOnline organisation (#142)

* Move remaining references to the HamRadioOnline organisation

The repository moved from praktimarc/kst4contest to
HamRadioOnline/kst4contest. Document the move in the German and English
changelog, point manuals, README, website, AUR packaging and the
version-feed tooling at the new address, and keep accepting pre-move
release URLs in the update-feed validator because published feeds still
carry the old owner. Personal identities (Ko-Fi account, contact
e-mail) stay unchanged.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WFGQ7wkSPo21itLMHPi8Yw

* Lowercase the owner in the generated Flatpak Pages URL

GITHUB_REPOSITORY_OWNER is now the mixed-case HamRadioOnline, and the
next build would write that spelling into the published flatpakrepo and
flatpakref files. Hostnames are case-insensitive, but the published
metadata should match the documented lowercase address.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WFGQ7wkSPo21itLMHPi8Yw

* Build the Flatpak against org.freedesktop.Platform 25.08

Runtime branch 24.08 is end-of-life and no longer receives security
updates, so every flatpak update now prints an EOL warning. 25.08 is
the current supported branch on Flathub. The app bundles its own Java
runtime, so the platform bump only changes the base libraries.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WFGQ7wkSPo21itLMHPi8Yw

---------

Co-authored-by: Claude <noreply@anthropic.com>

docs/PROJECT_CONTEXT.md

@@ -389,6 +389,12 @@ Before implementing planned items, re-check current decisions and obtain a fresh
 
 ## Recent Significant Changes
 
+### 2026-10-17 – Repository moved to the HamRadioOnline organisation
+
+- The GitHub repository moved from `praktimarc/kst4contest` to `HamRadioOnline/kst4contest`. GitHub redirects the old repository, Pages, API and git URLs, so published links and release assets from before the move keep working.
+- The Flatpak OSTree repository (branch `flatpak-repo`, served through GitHub Pages) is reached at `https://hamradioonline.github.io/kst4contest/`; its `kst4contest.flatpakrepo` and flatpakref metadata carry the new URL. Existing Flatpak remotes added under `praktimarc.github.io` keep updating through the Pages redirect.
+- `website/scripts/validate-version-info.js` accepts release URLs from both owners because update feeds published before the move still carry the old one.
+
 ### 2026-08-25 – Durable project context introduced
 
 - Added a persistent technical context layer so future agents/developers can understand architecture, invariants and cross-project dependencies without replaying chat history.