chore(fdroid): single-source fastlane metadata + reproducible-build prep

Make fastlane/metadata/android/ the single source of truth for store
listing metadata, consumed directly by the official F-Droid repo and
transformed into the self-hosted repo's localized layout at release time.

- Move fdroid-metadata/<appid>/<locale>/ -> fastlane/metadata/android/<locale>/
  (git-tracked renames: summary->short_description, description->full_description,
  + title.txt, images/icon.png, images/phoneScreenshots/); keep the app-level
  .yml control file for the self-hosted `fdroid update`.
- Add scripts/fastlane_to_fdroid_localized.sh (fastlane -> F-Droid localized,
  incl. changelogs) and scripts/sync_changelog_to_fastlane.sh (CHANGELOG.md ->
  fastlane changelog); verified byte-identical to the previous metadata.
- release.yaml: build self-hosted metadata from the fastlane tree and sync the
  per-version changelog before the transform (one changelog source for both
  channels).
- Disable AGP VCS-info embedding on release builds (vcsInfo { include = false })
  so builds reproduce byte-for-byte vs the distributed APK — the only file that
  otherwise differed (META-INF/version-control-info.textproto). Effective from
  the next release.
- Add docs/fdroid-official/ (draft fdroiddata recipe: reproducible build +
  AllowedAPKSigningKeys + Binaries + notes).
- Repoint README screenshots/icon, update docs/README + RELEASING, and skip the
  Android build on fastlane-only changes (ci.yaml).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

docs/README.md

@@ -12,7 +12,9 @@ Where to look for what:
 | [`../.planning/STATE.md`](../.planning/STATE.md) | Snapshot of where development currently stands |
 | [`superpowers/specs/`](superpowers/specs/) | The original design spec (2026-06-08) — historical record, not updated |
 | [`superpowers/plans/`](superpowers/plans/) | Per-milestone implementation plans with task checklists — historical record of how each slice was built, including provider lessons learned |
-| [`../fdroid-metadata/`](../fdroid-metadata/) | F-Droid/fastlane store metadata: descriptions, icon, screenshots (DE + EN) |
+| [`../fastlane/metadata/android/`](../fastlane/metadata/android/) | Store metadata (single source of truth): descriptions, title, icon, screenshots (DE + EN). Harvested directly by the official F-Droid repo; transformed into the self-hosted repo layout at release time by [`../scripts/fastlane_to_fdroid_localized.sh`](../scripts/fastlane_to_fdroid_localized.sh) |
+| [`../fdroid-metadata/`](../fdroid-metadata/) | App-level F-Droid control file (`*.yml`: Categories, License, links) for the self-hosted repo's `fdroid update` |
+| [`fdroid-official/`](fdroid-official/) | Draft recipe + notes for publishing to the **official** F-Droid repo (reproducible build + developer-signed binary) |
 
 Conventions: plans and specs under `superpowers/` are point-in-time
 artifacts of the agentic workflow that built each milestone — they get

docs/RELEASING.md

@@ -33,7 +33,15 @@ Published version codes so far: `v0.1.0`→100 … `v1.0.0`→10000 … `v2.0.0`
    the F-Droid per-version changelog.
 3. Bump the committed `versionName` (and `versionCode`) in
    `app/build.gradle.kts` to the new version. **This bump is what triggers the
-   release** when the branch merges to `main`.
+   release** when the branch merges to `main`. Then run
+   ```bash
+   scripts/sync_changelog_to_fastlane.sh
+   ```
+   and commit the generated
+   `fastlane/metadata/android/en-US/changelogs/<versionCode>.txt`. This is what
+   makes the **official** F-Droid repo show this version's changelog (it reads
+   the changelog from the tagged source tree). The self-hosted pipeline
+   regenerates it regardless, so forgetting only affects the official listing.
 4. **Verify the release build on a real device** — the mandatory gate. The
    shipped APK is R8-shrunk/obfuscated, and bugs that only appear there, or
    only on first run, never show up in the debug build or on a device that

docs/fdroid-official/README.md

@@ -0,0 +1,94 @@
+# Official F-Droid submission (draft)
+
+Goal: publish Calendula to the **official F-Droid repo** *alongside* the
+self-hosted repo, as **one app** — same signed binary in both channels, so
+existing self-hosted users migrate with no reinstall and no data loss.
+
+This folder holds the **draft** fdroiddata recipe. Nothing here is submitted
+yet. The self-hosted pipeline (`../../fdroid-metadata/`, `.gitea/workflows/release.yaml`)
+is unaffected by these files.
+
+## Publishing model: reproducible build + developer-signed binary
+
+F-Droid builds Calendula from source on its buildserver, then verifies the
+output is byte-for-byte identical to **our** signed APK (fetched via the
+`Binaries` URL). On a match it publishes **our** binary, signed with **our**
+key — identified by `AllowedAPKSigningKeys`. Result: official and self-hosted
+both carry the same signature. If a build ever fails to match, F-Droid simply
+skips that version (fails safe — no bad publish).
+
+## Verification status (2026-06-21)
+
+- ✅ **Run-to-run reproducible** — `v2.7.0` built twice from a clean worktree
+  (R8 minify + resource-shrink, build cache off) → byte-for-byte identical
+  (`sha256 568c944a…`).
+- ✅ **Cross-JDK reproducible** — rebuilt with JDK 17 and JDK 21 → identical
+  APK. JDK version is not a sensitivity, so it need not be pinned.
+- ✅ **Tag self-consistent** — committed `versionCode`/`versionName` already
+  equal the tag-derived values, so F-Droid building the tag as-is matches the
+  CI-published binary (CI's `sed` substitution is a no-op).
+- ✅ **App signing cert SHA-256 extracted** from published APKs (identical
+  across v1.0.0 / v2.0.0 / v2.4.0): `5cdaee8e…`. No keystore needed.
+- ✅ **Eligibility** — MIT, 100% FOSS deps (no Play Services / Firebase /
+  analytics / billing), no `INTERNET` permission, no native code.
+- ✅ **End-to-end reproducible vs the DISTRIBUTED binary** — built tag `v2.7.1`
+  from source and compared against the published `calendula_v2.7.1.apk`: every
+  app entry (dex / resources / assets / manifest) byte-identical. The only
+  difference was `META-INF/version-control-info.textproto` (AGP's git metadata,
+  env-dependent). Fixed with `vcsInfo { include = false }` on the release build;
+  re-validated → 0 non-signature differences. **Takes effect from the first
+  release built after that change — submit the recipe starting at that version**
+  (v2.7.1 and earlier still embed the textproto and won't verify).
+- ⚠️ **Not yet proven**: cross-host / fixed-build-path reproducibility on
+  F-Droid's buildserver (low risk for a no-NDK pure-JVM app; with vcsInfo
+  disabled, the env-dependent field is gone; F-Droid confirms at review).
+- ✅ **Buildserver toolchain supported** (checked 2026-06-21):
+  - **Gradle 9.5.1** is in F-Droid's gradle-transparency-log (`checksums.json`)
+    with a verified sha256, so `gradlew.py` will download + verify + run it.
+  - **AGP 9.2** is in `gradlew.py`'s `MIN_GRADLE_VERSION` map (`9.2 -> 9.4.1`).
+  - **JDK 17** is standard on the buildserver (AGP 9.2 requires exactly 17).
+  - **build-tools 36.0.0 / android-37**: not statically preinstalled (baseline
+    stops at 33), but `provision-android-sdk` makes `$ANDROID_HOME/build-tools`
+    and `/platforms` group-writable so AGP/Gradle install newer ones on demand.
+
+## Before submitting — checklist
+
+1. Confirm the `Binaries` URL is publicly reachable and stable long-term, e.g.
+   `https://apps.dev.jeanlucmakiola.de/dev/fdroid/repo/calendula_v2.7.0.apk`
+   resolves to the dev-signed APK. F-Droid re-fetches it on every build.
+2. Confirm F-Droid's buildserver supports the toolchain (see timing risk).
+3. (Recommended) Reproduce one published release end-to-end: build the tag from
+   source, strip signatures, and diff against the downloaded `calendula_v<ver>.apk`
+   to confirm the from-source build matches the *distributed* binary — not just
+   another local build.
+
+## Submission steps (fdroiddata, GitLab)
+
+1. Fork `https://gitlab.com/fdroid/fdroiddata`.
+2. Copy `de.jeanlucmakiola.calendula.yml` to `metadata/` in the fork.
+3. Test locally with `fdroid build -v de.jeanlucmakiola.calendula` and
+   `fdroid lint de.jeanlucmakiola.calendula` (and `fdroid readmeta`).
+4. Open a Merge Request. Initial review can take weeks to months; the
+   self-hosted repo keeps serving in the meantime, so there's no rush.
+
+## Listing metadata (descriptions, screenshots, icon)
+
+These are **not** in the recipe `.yml`. F-Droid's `fdroid update` harvests them
+automatically from the fastlane tree in the app's source repo:
+
+    fastlane/metadata/android/<locale>/
+      short_description.txt   full_description.txt   title.txt
+      images/icon.png         images/phoneScreenshots/*.png
+      changelogs/<versionCode>.txt   (optional, per release)
+
+This is the single source of truth: en-US + de-DE already exist there, and the
+self-hosted repo is generated from the same tree at release time via
+`scripts/fastlane_to_fdroid_localized.sh`. Nothing extra to add to fdroiddata —
+F-Droid picks the listing up from source. (Screenshots may not be committed to
+the fdroiddata repo anyway, so the source-tree fastlane layout is required.)
+
+Per-version changelogs: the self-hosted release workflow generates
+`changelogs/<versionCode>.txt` at release time. For the official repo to show a
+changelog, that file must be committed into `fastlane/metadata/android/<locale>/changelogs/`
+at the tagged commit — wire this into the release/version-bump step, or accept
+no in-client changelog for the official listing initially.

docs/fdroid-official/de.jeanlucmakiola.calendula.yml

@@ -0,0 +1,58 @@
+# ---------------------------------------------------------------------------
+# DRAFT fdroiddata metadata for the OFFICIAL F-Droid repository.
+#
+# This is NOT the self-hosted metadata (that lives in ../../fdroid-metadata/).
+# When submitting, this file's contents go to fdroiddata on GitLab as
+#   metadata/de.jeanlucmakiola.calendula.yml
+# See README.md in this folder for the verification status and submission steps.
+#
+# Publishing model: REPRODUCIBLE BUILD + developer-signed binary.
+# F-Droid builds from source on its buildserver, then verifies the result is
+# identical to our own signed APK (fetched via `Binaries`). If it matches,
+# F-Droid publishes OUR binary signed with OUR key (`AllowedAPKSigningKeys`),
+# so the official and self-hosted channels carry the SAME signature and users
+# migrate between them with no reinstall / no data loss.
+# ---------------------------------------------------------------------------
+
+Categories:
+  - Time
+License: MIT
+AuthorName: Jean-Luc Makiola
+SourceCode: https://gitea.jeanlucmakiola.de/makiolaj/calendula
+IssueTracker: https://gitea.jeanlucmakiola.de/makiolaj/calendula/issues
+Changelog: https://gitea.jeanlucmakiola.de/makiolaj/calendula/src/branch/main/CHANGELOG.md
+
+AutoName: Calendula
+
+RepoType: git
+Repo: https://gitea.jeanlucmakiola.de/makiolaj/calendula.git
+
+# IMPORTANT: the first build entry MUST target the first release that contains
+# `vcsInfo { include = false }` (added on branch chore/release-verification-process).
+# v2.7.1 and earlier embed META-INF/version-control-info.textproto, whose
+# env-dependent git metadata breaks reproducibility — they will NOT verify.
+# Update the versionName/versionCode/commit/Binaries below once that release is
+# tagged (e.g. v2.7.2 -> versionCode 20702). Values below are placeholders.
+Builds:
+  - versionName: 2.7.2
+    versionCode: 20702
+    commit: v2.7.2
+    subdir: app
+    gradle:
+      - yes
+    # No NDK / no flavors. The release buildType applies a signingConfig only
+    # when key.properties exists; on the buildserver it does not, so this
+    # produces the unsigned APK F-Droid compares against our binary.
+
+# SHA-256 of our app signing certificate (public; embedded in every published
+# APK). Locks F-Droid to publish only binaries signed with our key.
+AllowedAPKSigningKeys: 5cdaee8eb31cb0df9157c646ae3ec8b3dc43b5bb72624e088c9ddea0c4eb5ec1
+
+# Our own developer-signed APK for reproducible-build verification. %v -> the
+# versionName, so v2.7.2 resolves to calendula_v2.7.2.apk on the self-hosted repo.
+Binaries: https://apps.dev.jeanlucmakiola.de/dev/fdroid/repo/calendula_v%v.apk
+
+AutoUpdateMode: Version v%v
+UpdateCheckMode: Tags
+CurrentVersion: 2.7.2
+CurrentVersionCode: 20702