feat(assistant)!: no hand-off and no connector; the field searches the web (ADR 0022)

The developer decided on 23 Oct to drop the hand-off to an AI assistant
outside the app, and Claude's connector with it, in v0.19.0, the app and
the server together: build 22 raises minimumAppBuild anyway, so no app
calling the connector's endpoints uses the instance after it. An instance
is to have one way to an assistant, its operator's (ADR 0021, proposed).

The app: the field at the foot of Home, and the button in the Library, on
a studyset and while studying, search the web alone, through the engine
chosen in Settings or Android's own search, with the parts of a card the
person picks; a studyset's name and description are never offered. Gone:
the assistants a question opened in (AiAssistant, AssistantHandOff), the
switch between them and the web, Settings' choice of assistant, Connect
Claude with its route, cubit, repository and gateway, and their texts. A
settings file from before keeps the old keys until the next change of a
setting writes it anew; nothing reads them.

The server: lib/src/assistant/ (MCP, its OAuth, the five tools, connect
codes and tokens), AssistantEndpoint, the daily forgetting of the
connector's secrets (its scheduled call cancelled at start), its lines in
the deletion hook, instance.info().assistantConnectorUrl (nullable, so an
older app reads it as none), and Caddy's forwarding of /mcp, /oauth/* and
/.well-known/oauth-*. The migration drops the connector's five tables,
children first:

  DROP TABLE "assistant_token" CASCADE;       -- tokens of a connection
  DROP TABLE "assistant_grant" CASCADE;       -- OAuth codes of a connection
  DROP TABLE "assistant_connection" CASCADE;  -- a person's connected client
  DROP TABLE "assistant_connect_code" CASCADE;
  DROP TABLE "assistant_client" CASCADE;      -- OAuth clients registered

No other table references them, so CASCADE drops only their own foreign
keys. For the minute between the maintenance run and the switch, the old
server answers the connector with errors and fails to delete an account
(its hook still deletes from these tables); ADR 0022 says so.

BREAKING CHANGE: a connected Claude gets no answer from the deploy on, and
the app no longer opens a question in an AI assistant.

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

packages/halkyon_base_server/lib/src/common/short_code.dart

@@ -1,8 +1,8 @@
 import 'dart:math';
 
 /// Short codes people type, read off a screen or out of a mail: email
-/// sign-in's codes, and whatever a host has people type likewise (Halkyon
-/// Learn's connect codes). Keep them only hashed.
+/// sign-in's codes, and whatever a host has people type likewise. Keep them
+/// only hashed.
 
 final _random = Random.secure();
 

packages/halkyon_base_server/lib/src/profile/profile_page.dart

@@ -59,8 +59,8 @@ Future<({int status, String html, String? location})> profilePage(
 }
 
 /// Serves profile pages on [pod]'s web server, at `/@handle`: one path
-/// segment, which a host's literal routes come before (Halkyon Learn: its
-/// assistant connector's). Caddy forwards `/@…` to it (the host's
+/// segment, which a host's literal routes come before (Halkyon Learn: the
+/// register's calls). Caddy forwards `/@…` to it (the host's
 /// `deploy/Caddyfile`).
 void addProfilePageRoute(Serverpod pod) {
   if (pod.config.webServer == null) {