feat(learn,todo,meditate): dictate through the phone's voice input app (ADR 0038, D18)

On Android the microphone now opens the app handling
RECOGNIZE_SPEECH (FUTO Voice Input, Google's), the default the person
chose in Android, and puts the text it returns where the cursor stood,
as Dictation does; cancelled, nothing. Only where none is installed, or
it can't be opened, does speech_to_text listen in line as before.

halkyon_app: VoiceInputApp (one listen, an answer once closed) on the
channel app.halkyon/voice_input, which DeviceSpeechInput asks first at
every listen, answering SpeechStart.finished so that Dictation doesn't
listen again; speech_to_text isn't touched on that route, so our app
asks for no microphone. SpeechInput.listen and Dictation.start take the
prompt the voice input app shows (the field's hint).

Each app: VoiceInput.kt (queryIntentActivities, startActivityForResult,
the first of EXTRA_RESULTS) attached in MainActivity, which hands it
activity results, and RECOGNIZE_SPEECH among the manifest's queries.
The privacy pages of Learn and Meditate say so.

Our own Whisper and Meditate's dream recordings are dropped (D18).

Whats-New: The microphone now dictates through your phone's voice input app, such as FUTO Voice Input.
Whats-New-De: Das Mikrofon diktiert jetzt über die Spracheingabe-App deines Telefons, etwa FUTO Voice Input.
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

@@ -10,7 +10,7 @@ Halkyon's apps and the packages they share, in one repository and one pub worksp
 - **`packages/`**: what the apps share, each with its README and licence, which the apps take by path (`path: ../../../packages/<package>`), so a change to a shared package and to the apps using it is one commit:
   - `halkyon_ui`: Halkyon's look, the theme around cobalt and copper, Noto Sans bundled, the window-size classes and the widgets every screen is built of (the navigation bar flush with the foot with its fade, and the rail, `FoldingTabs`' tab row folding into the title), with texts of its own (English, German).
   - `halkyon_base_server`, `halkyon_base_client`: the Serverpod module every Halkyon server includes (ADR 0014): signing in (a password with TOTP and the resets of ADR 0017, SimpleLogin on `halkyon_oidc`, email codes proving an address; no anonymous accounts since ADR 0020, D25, nor GitHub since D36), an account's ways in and its deletion with a hook for each app's own data, the pruning, the instance's basics, people's handles and public profiles, who may sign up (`SIGN_UP`: open, approval, closed) with the accounts waiting for approval and the instance's operators who approve them (Halkyon Learn's ADR 0021, step 1), the operator's assistants forwarded on halkyon_llm with their grants, each person's budget, the efforts they allow and counted figures, and the instance's privacy page made from its settings (step 2), and the instance's register (ADR 0016): one account per person across an operator's services, held by one service (Learn's server on learn.halkyon.eu) and asked by the others, its members (`ACCOUNT_REGISTER_URL`), all sharing a secret (`INSTANCE_SECRET`); its README says how.
-  - `halkyon_app`: every app's shell on the module's client (ADR 0014): the instances a device keeps accounts on and the first start, signing in and switching person, the gates building an app's dependencies per instance and per person, the sync service and where it stands, the account section of an app's settings (`AccountTiles`), every app's Profile (`HalkyonProfile`, decided 2026-11-02: the person's own tab, the same in every app, with their account, the ways they sign in and their public profile, one for all apps, then the app's own tabs) and people's public profiles (`PublicProfileRepository`, `PublicProfileSection`, `showProfileOf`), the wait screen of an account waiting for approval and the operator's card, badge and screen (ADR 0021), the assistants of an app's settings (`AssistantsCard`: granted, by provider, agreed to, what is left of the person's budget, used, and the person's own keys) and the operator's grants from that screen (`AssistantGrantsScreen`: several assistants to several people at once, each with one budget, D57 to D63), with the repositories asking them through the module, at an effort the operator allows, or a person's own key directly (step 2) and what an app's warning before a private studyset goes names (`providerTermsOf`, `OwnAssistant.onThisMachine`, step 3), About with the instance's source link (`showAppAbout`), the device's own speech recognition (`SpeechInput`, `DeviceSpeechInput` on `speech_to_text`, `FakeSpeechInput` in `testing.dart`; none on Linux) and dictation into a text at its cursor, listening again after each pause (`Dictation`, Meditate's ADR 0038, D15; an app that listens declares the microphone and its usage texts itself), what's new after an update (`WhatsNew`, `WhatsNewOnUpdate`, `WhatsNewTile`, from the app's `assets/whats_new/`, Train's ADR 0030, D61), the device's appearance and language, chosen in Settings and applied before anyone signs in (`Look`, `FileLookStore`, `LookCubit`, `DeviceLookCard`; Learn keeps them among its own device settings and shows `LookSettingsCard`; ADR 0014's amendment of 4 Nov 2026), the language every app picks (`resolveAppLocale`) and countries' and subdivisions' names (Unicode CLDR's, bundled), with texts that name the app.
+  - `halkyon_app`: every app's shell on the module's client (ADR 0014): the instances a device keeps accounts on and the first start, signing in and switching person, the gates building an app's dependencies per instance and per person, the sync service and where it stands, the account section of an app's settings (`AccountTiles`), every app's Profile (`HalkyonProfile`, decided 2026-11-02: the person's own tab, the same in every app, with their account, the ways they sign in and their public profile, one for all apps, then the app's own tabs) and people's public profiles (`PublicProfileRepository`, `PublicProfileSection`, `showProfileOf`), the wait screen of an account waiting for approval and the operator's card, badge and screen (ADR 0021), the assistants of an app's settings (`AssistantsCard`: granted, by provider, agreed to, what is left of the person's budget, used, and the person's own keys) and the operator's grants from that screen (`AssistantGrantsScreen`: several assistants to several people at once, each with one budget, D57 to D63), with the repositories asking them through the module, at an effort the operator allows, or a person's own key directly (step 2) and what an app's warning before a private studyset goes names (`providerTermsOf`, `OwnAssistant.onThisMachine`, step 3), About with the instance's source link (`showAppAbout`), the device's own speech recognition (`SpeechInput`, `DeviceSpeechInput`: on Android the voice input app handling `RECOGNIZE_SPEECH` where one is installed, `VoiceInputApp` on each app's `VoiceInput.kt`, `app.halkyon/voice_input`, FUTO Voice Input for one, which records itself and returns text, else `speech_to_text`; `FakeSpeechInput` in `testing.dart`; none on Linux; Meditate's ADR 0038, D18) and dictation into a text at its cursor, listening again after each pause (`Dictation`, Meditate's ADR 0038, D15; an app that listens declares the microphone and its usage texts itself), what's new after an update (`WhatsNew`, `WhatsNewOnUpdate`, `WhatsNewTile`, from the app's `assets/whats_new/`, Train's ADR 0030, D61), the device's appearance and language, chosen in Settings and applied before anyone signs in (`Look`, `FileLookStore`, `LookCubit`, `DeviceLookCard`; Learn keeps them among its own device settings and shows `LookSettingsCard`; ADR 0014's amendment of 4 Nov 2026), the language every app picks (`resolveAppLocale`) and countries' and subdivisions' names (Unicode CLDR's, bundled), with texts that name the app.
   - `halkyon_editor` (ADR 0033, D37, 6 Nov 2026): rich text, the general parts of Learn's editor on our fork of `appflowy_editor`: `RichContent` (the editor's document JSON, which Learn and Todo store), `RichContentEditor`, `RichContentView`, the format bar, links, the clipboard keeping formats, superscript and subscript, and `EditorBlocks`, through which an app adds blocks, marks within lines and their buttons (`basicBlocks` without any), with texts of its own (English, German). What is Learn's alone stays in Learn on top of it.
   - `halkyon_core` (low-level primitives in pure Dart: ids, a logger, `SerialQueue`, `CoalescingRunner`) and `halkyon_interop` (contracts between apps, pure Dart).
   - `halkyon_keys` (pure Dart on libsodium, ADR 0017): an account's keys on the device, the password's Argon2id and SRP's x, the key pairs and their wrapping, the recovery phrase, data keys, content sealed and signed, row IDs keyed by the account (`keyedRowId`). SRP-6a's two halves are the module's (`halkyon_base_server`'s `base.dart`, `halkyon_base_client`'s `srp.dart`), as are TOTP and the recovery codes. `sodium`'s build hook compiles libsodium, so every machine that builds or tests needs a C compiler and `make`.