build: releases fetch their signing keys from Proton Pass into memory, never onto the disk

tool/with_signing_keys.sh downloads the app's Android keystore and the
F-Droid index's from the vault Infra · Signing into a folder under
$XDG_RUNTIME_DIR, runs tool/release.dart with their paths, and removes
the folder however the run ends. The passwords are asked for as ever.

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

AGENTS.md

@@ -82,7 +82,7 @@ Checklist after doing changes, in this order:
 - Check `serverpod` MCP `tail_server_logs` and `tail_flutter_logs` for any issues.
 
 - **Melos** (decided 2026-10-19, ADR 0015) runs scripts across the workspace's packages: a dev dependency of the root (`dart run melos …`, its version in the lock), its scripts under `melos:` in the root `pubspec.yaml`: `analyze`; `test:dart` (the packages without Flutter, one at a time, as each server's tests start a PostgreSQL of their own on the same port); `test:flutter` (`flutter test -x requires-server`, one package at a time); `generate` (Serverpod's code generation in every package with a `config/generator.yaml`, the CLI on the PATH); `check` (`tool/check.dart`). Every script takes Melos' filters: `dart run melos run test:flutter --scope=halkyon_app`, or `--diff=origin/main --include-dependents` for what changed and what depends on it; `dart run melos list` lists the packages. The root overrides `cli_util` to 0.5.2 for it: Learn's `flutter_launcher_icons` (0.14.4, its latest) asks for ^0.4.1 and uses only the logger, which 0.5 keeps; drop the override once that package allows 0.5.
-- **Tools are Dart where they hold logic** (decided 2026-10-19): conditions, parsing, parallel work, anything worth a test, as `tool/check.dart` (its file selection in `tool/src/check_files.dart`, tested in the root's `test/`). **Bash for glue**, short and linear (`tool/pre-push`, `tool/check_signatures.sh`, `tool/workspace_only.sh`, which narrows the root pubspec's workspace to the packages an image builds), **and for everything run on the production host**, which has no Dart SDK and gets none (`deploy/redeploy.sh`, `deploy/backup.sh`). **Python only where a library exists only there** (the apps' icons with librsvg and Pillow, `tool/app_icons.py`, its Anki fixtures with Anki itself); Learn's data scripts and `packages/halkyon_app/tool/subdivision_names.py` need nothing but Python's standard library and may move to Dart when they next change. **Releases come from `tool/release.dart`** (decided 2026-10-19, ADR 0015), shared by the apps, each configured in Dart beside it (`apps/<id>/release.dart`, typed and commented, registered in `tool/src/release/apps.dart`): `dart run tool/release.dart learn [major | minor | patch] [--dry-run]`, on a developer's laptop, never in CI. Tags are per app (`learn-v0.19.0`; an app's earlier tags, Learn's `v…`, count as its history), and only commits touching the app decide its version: its folder, the shared packages its packages use by path (transitively), the root pubspec and lock, its release files (key pins, F-Droid listing, snap recipe) and where its packages were before a move. `--dry-run` reads everything a release would (the version, the commits that count and what each touches, the steps, the notes it would publish), changes nothing, asks for no secret, and lists what a release would refuse. Its pure logic is in `tool/src/release/`, tested in the root's `test/release/`. `tool/fdroid_repo.sh` stays Bash (glue for fdroidserver). Build 21 (`v0.18.0`) was the last release of `tool/release.sh`, the Bash script it replaced, removed since.
+- **Tools are Dart where they hold logic** (decided 2026-10-19): conditions, parsing, parallel work, anything worth a test, as `tool/check.dart` (its file selection in `tool/src/check_files.dart`, tested in the root's `test/`). **Bash for glue**, short and linear (`tool/pre-push`, `tool/check_signatures.sh`, `tool/workspace_only.sh`, which narrows the root pubspec's workspace to the packages an image builds), **and for everything run on the production host**, which has no Dart SDK and gets none (`deploy/redeploy.sh`, `deploy/backup.sh`). **Python only where a library exists only there** (the apps' icons with librsvg and Pillow, `tool/app_icons.py`, its Anki fixtures with Anki itself); Learn's data scripts and `packages/halkyon_app/tool/subdivision_names.py` need nothing but Python's standard library and may move to Dart when they next change. **Releases come from `tool/release.dart`** (decided 2026-10-19, ADR 0015), shared by the apps, each configured in Dart beside it (`apps/<id>/release.dart`, typed and commented, registered in `tool/src/release/apps.dart`): `dart run tool/release.dart learn [major | minor | patch] [--dry-run]`, on a developer's laptop, never in CI, through `tool/with_signing_keys.sh learn …` (Bash glue): the keystores are kept in Proton Pass alone (vault *Infra · Signing*, each a note's attachment, the password its hidden field), and it downloads the app's and the F-Droid index's into a folder in memory (`$XDG_RUNTIME_DIR`), hands their paths to the release tool and removes them however the run ends (`test/release/signing_keys_test.dart` holds it to every app released). Tags are per app (`learn-v0.19.0`; an app's earlier tags, Learn's `v…`, count as its history), and only commits touching the app decide its version: its folder, the shared packages its packages use by path (transitively), the root pubspec and lock, its release files (key pins, F-Droid listing, snap recipe) and where its packages were before a move. `--dry-run` reads everything a release would (the version, the commits that count and what each touches, the steps, the notes it would publish), changes nothing, asks for no secret, and lists what a release would refuse. Its pure logic is in `tool/src/release/`, tested in the root's `test/release/`. `tool/fdroid_repo.sh` stays Bash (glue for fdroidserver). Build 21 (`v0.18.0`) was the last release of `tool/release.sh`, the Bash script it replaced, removed since.
 
 ## CI and deploys