feat: the F-Droid repository moves to halkyon.app

The repository is Halkyon's, for all of its apps, so its address is the
brand's: https://halkyon.app/fdroid/repo. learn.halkyon.app stays Halkyon
Learn's own address, for its website later. Moved before anyone but the
maintainer had added it; the address is permanent once people have.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>

tool/fdroid_repo.sh

@@ -1,5 +1,5 @@
 #!/usr/bin/env bash
-# Updates the F-Droid repository at https://learn.halkyon.app/fdroid/repo and
+# Updates the F-Droid repository at https://halkyon.app/fdroid/repo and
 # uploads it: adds an APK if one is given, signs the index with the repository's
 # key, and uploads everything to ramiel as the user fdroid, whose key can only
 # write into the folder Caddy serves (rrsync). tool/release.sh runs it with each
@@ -26,7 +26,7 @@ keystore="${HALKYON_FDROID_KEYSTORE:-$HOME/.local/share/halkyon-learn/fdroid-ind
 readonly key_alias='halkyon-fdroid'
 readonly pinned_file='tool/release/fdroid-index-certificate.sha256'
 readonly upload_host='ramiel-fdroid'
-readonly repo_url='https://learn.halkyon.app/fdroid/repo'
+readonly repo_url='https://halkyon.app/fdroid/repo'
 
 fail() {
   echo "✗ $*" >&2

tool/release.sh

@@ -2,7 +2,7 @@
 # Builds a release and publishes it: the Android APK (one for every phone, signed with
 # the app's key) and the Linux snap, both connecting to learn.halkyon.eu, the project's
 # instance; a list of their checksums signed with GPG; all of it as a release on
-# code.halkyon.app, the APK in the F-Droid repository at learn.halkyon.app
+# code.halkyon.app, the APK in the F-Droid repository at halkyon.app
 # (tool/fdroid_repo.sh), and the snap in the Snap Store's edge channel. Run on a
 # developer's laptop, never in CI: the app's key never leaves it.
 #
@@ -198,7 +198,7 @@ the project's instance.
 - **Android:** \`$apk\`, one APK for every phone, signed with the app's key; the \
 SHA-256 of its certificate is \`$certificate\`.
 - **F-Droid:** the same APK in the repository \
-https://learn.halkyon.app/fdroid/repo?fingerprint=$fdroid_fingerprint
+https://halkyon.app/fdroid/repo?fingerprint=$fdroid_fingerprint
 - **Linux:** \`$snap\`, also in the Snap Store: \`snap install halkyon-learn --edge\`.
 
 \`SHA256SUMS\` lists the files' checksums, signed with the GPG key \`$signer\` \

tool/release/fdroid-index-certificate.sha256

@@ -1,5 +1,5 @@
 # The SHA-256 of the certificate that signs the indexes of the F-Droid repository at
-# https://learn.halkyon.app/fdroid/repo (key alias halkyon-fdroid), as keytool prints it.
+# https://halkyon.app/fdroid/repo (key alias halkyon-fdroid), as keytool prints it.
 # The F-Droid app knows the repository by it; tool/fdroid_repo.sh uploads no index
 # signed otherwise.
 E8:08:27:88:75:6F:6B:7E:68:2A:A2:2F:CE:AD:24:B5:3E:2A:8B:09:12:AD:66:D6:5E:8C:2D:4F:07:BB:94:B0

tool/release/fdroid/config.yml

@@ -1,9 +1,10 @@
-# The F-Droid repository at https://learn.halkyon.app/fdroid/repo, kept by
+# The F-Droid repository at https://halkyon.app/fdroid/repo, for all of
+# Halkyon's apps, kept by
 # tool/fdroid_repo.sh: this folder is copied into the repository's working
 # folder (outside Git) before every update. Nothing secret is in here: the index
 # key's path and password come from the environment.
-repo_url: https://learn.halkyon.app/fdroid/repo
-archive_url: https://learn.halkyon.app/fdroid/archive
+repo_url: https://halkyon.app/fdroid/repo
+archive_url: https://halkyon.app/fdroid/archive
 repo_name: Halkyon
 repo_description: >-
   Halkyon's apps, signed by their maintainer: the same APKs as on