refactor!: packages, paths and app IDs under Halkyon Days' names (ADR 0045, step 3)

Learn's folder is apps/halkyon, Todo's apps/myrmex; every package of
ours takes the prefix halkyone_ (halkyone_halkyon_*, halkyone_myrmex_*,
halkyone_train_*, halkyone_meditate_*, halkyone_app, halkyone_base_* and
the other shared ones; halkyon_oidc_* keeps its name, D11). Halkyon and
Myrmex take the app IDs one.halky.halkyon and one.halky.myrmex (D10);
Train and Meditate keep theirs, while every app's Android namespace,
Kotlin package and method channels move to one.halky. The snaps are
halkyon and myrmex (D17), each built in a clone with its recipe in
place of snap/, as Train's and Todo's were.

Serverpod finds a database's migrations by its module's name, which
changed with the packages':
- each server's new, empty migration ("rename") records itself under
  the new names and deletes the rows under the old ones;
- deploy/redeploy.sh copies each database's record to the new name
  before the migrations (carry_module), so the renamed servers find
  their databases migrated; a copy, never a move, so a deploy failing
  before the migration commits leaves the old rows in place;
- Train and Meditate keep their devices' databases: halkyone_app's
  carryMigrationRecord copies their record before the sync engine
  opens them (openPersonDatabase);
- the client migrations' generated moduleName getters, one line each,
  say the new names: Serverpod's client asserts in debug builds that
  every migration names the module, and create-migration never writes
  a migration's files again.

Train's WorkManager work is enqueued under new names, the former ones
cancelled: the work kept names the workers' former classes.

The release tool: an app's tags of its earlier names count as its
history (legacyTagPrefixes), the shared packages' former paths count
for its version, and every snap is built in a clone (atRoot gone).

The databases, Docker images and Compose project keep their names
until step 5.

BREAKING CHANGE: Halkyon (Learn) and Myrmex (Todo) are new apps to
Android and the Snap Store: installs of app.halkyon.learn and
app.halkyon.todo don't update to them.

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

apps/todo/halkyon_todo_flutter/pubspec.yaml

@@ -1,139 +0,0 @@
-name: halkyon_todo_flutter
-description: Halkyon Todo, the app.
-publish_to: none
-
-# <version>+<build>: the build rises with every release, and the instance asks apps below
-# its minimum build to update (halkyon_base's instance basics).
-version: 0.4.0+4
-
-environment:
-  sdk: '^3.13.0'
-  flutter: '^3.44.4'
-
-resolution: workspace
-
-dependencies:
-  # The chime of a task done on a desktop (decided 10 Nov 2026), as Learn's
-  # sounds: GStreamer on Linux.
-  audioplayers: ^6.8.1
-  clock: ^1.1.3
-  crypto: ^3.0.7
-  # Reactions on comments (ADR 0033, D36): every emoji, searched, recents on
-  # the device.
-  emoji_picker_flutter: ^4.5.4
-  equatable: ^3.0.0
-  flutter:
-    sdk: flutter
-  flutter_bloc: ^9.1.1
-  # Tasks' reminders, scheduled with the system on the device (ADR 0033, D5):
-  # the instance reads no task, so it can't remind of one.
-  flutter_local_notifications: ^22.3.3
-  # A task's location picked on a map (ADR 0033, D32), as Train's maps: the
-  # map widget, OpenFreeMap's vector tiles and their coordinates.
-  flutter_map: ^8.3.2
-  # The tabs, each with its own stack of screens, and Settings over them
-  # (ADR 0033, D1), as Learn's and Train's.
-  go_router: ^18.0.2
-  # What every Halkyon app is built around (a shared package): the instances a
-  # device keeps accounts on, signing in through halkyon_base, each person's
-  # dependencies opened and closed, with texts of its own.
-  halkyon_app:
-    path: ../../../packages/halkyon_app
-  # The device's half of signing in with OpenID Connect (ADR 0023): the
-  # browser that SimpleLogin's sign-in opens, and on Linux and Windows the
-  # loopback it comes back to, which the app builds with its name.
-  # Primitives every Halkyon package shares: `CoalescingRunner`.
-  halkyon_core:
-    path: ../../../packages/halkyon_core
-  # Comments and descriptions as rich text (ADR 0033, D38).
-  halkyon_editor:
-    path: ../../../packages/halkyon_editor
-  halkyon_oidc_flutter:
-    path: ../../../packages/halkyon_oidc_flutter
-  halkyon_todo_client:
-    path: ../halkyon_todo_client
-  # Halkyon's look, shared by its apps (a shared package): the theme, the bundled
-  # Noto Sans and the widgets every screen is built of.
-  halkyon_ui:
-    path: ../../../packages/halkyon_ui
-  # Calendars' feeds fetched by the device (ADR 0033, D39).
-  http: ^1.6.0
-  # gen-l10n's output imports it.
-  intl: ^0.20.3
-  latlong2: ^0.10.1
-  lucide_icons_flutter: ^3.1.20
-  material_ui: ^1.5.0
-  # This build's version and number, for Settings' foot and what's new.
-  package_info_plus: ^10.2.2
-  path: ^1.9.1
-  path_provider: ^2.1.6
-  rrule: ^0.2.18
-  serverpod_auth_idp_flutter: 4.0.4
-  serverpod_flutter: 4.0.4
-  serverpod_offline_sync_client: 0.0.10
-  # The instant a reminder is scheduled at, as flutter_local_notifications
-  # takes it (in UTC).
-  timezone: ^0.11.2
-  url_launcher: ^6.3.2
-  # Pinned as Train's: the 9 line is beta, the only one for flutter_map 8.
-  vector_map_tiles: 9.0.0-beta.13
-
-dev_dependencies:
-  flutter_driver:
-    sdk: flutter
-  # Writes the app's icons for every platform from assets/icon/halkyon_todo_icon.png,
-  # run through the repository's tool/app_icons.py (see the section below).
-  flutter_launcher_icons: ^0.14.4
-  flutter_test:
-    sdk: flutter
-
-  test: any
-  vector_tile_renderer: ^6.1.0
-flutter:
-  # Generates AppLocalizations from lib/l10n (see l10n.yaml).
-  generate: true
-  # Material's icon font, which serverpod_auth_idp_flutter's widgets ask for
-  # (it sets this itself): without it every build and test run warns, and
-  # Material's icons would draw as boxes.
-  uses-material-design: true
-
-  assets:
-    # The instance the build names, unless --dart-define=SERVER_URL=… does
-    # (serverpod_flutter's getServerUrl).
-    - assets/config.json
-    # What each release changed, one file a release and language
-    # (<version>.<language>.txt), drafted by tool/release.dart and edited
-    # (Train's ADR 0030, D61): halkyon_app's What's new shows them.
-    - assets/whats_new/
-    # The chime of a task done on a desktop, Todo's own, synthesized by
-    # ../tool/completion_sound.dart.
-    - assets/sounds/task_done.wav
-    # The app's icon, Lucide's list-todo (ADR 0031), and Lucide's licence for the
-    # licence list (the repository's tool/app_icons.py writes both).
-    - assets/icon/halkyon_todo_icon.png
-    - assets/icon/halkyon_todo_kingfisher.png
-    - assets/icon/LICENSE-lucide.txt
-
-# The app's icons, written by the repository's tool/app_icons.py: it prepares the
-# rounded images in build/icons/ first, then runs `dart run flutter_launcher_icons`.
-# Android: the adaptive icon, on white, for the launcher to cut to its shape, and the
-# square one older Androids show. iOS: without its alpha channel, on white. macOS and
-# Windows: the rounded tile.
-flutter_launcher_icons:
-  image_path: "assets/icon/halkyon_todo_icon.png"
-  android: true
-  adaptive_icon_background: "#ffffff"
-  adaptive_icon_foreground: "assets/icon/halkyon_todo_icon.png"
-  adaptive_icon_monochrome: "build/icons/monochrome.png"
-  ios: true
-  remove_alpha_ios: true
-  background_color_ios: "#ffffff"
-  image_path_ios_dark_transparent: "build/icons/ios_dark.png"
-  image_path_ios_tinted_grayscale: "build/icons/ios_tinted.png"
-  macos:
-    generate: true
-    image_path: "build/icons/macos.png"
-  windows:
-    generate: true
-    image_path: "build/icons/rounded.png"
-    icon_size: 256