feat: goals — "watch N movies in YEAR" with progress bar

Domain: Goal entity, UserSettings (federation toggle), RemoteGoalEntry.
Ports: GoalRepository, UserSettingsRepository, RemoteGoalRepository.
Adapters: sqlite + postgres repos, migrations, AP content query extensions.
Application: CRUD use cases (create/update/delete/get/list), settings use cases.
API: 7 endpoints (/goals CRUD, /users/{id}/goals, /settings) with utoipa docs.
Federation: GoalObject (Note + goal discriminator), outbound broadcast with
per-user toggle, inbound GoalObjectHandler in CompositeObjectHandler.
SPA: API client + hooks, GoalCard (shadcn Card+Progress+DropdownMenu),
GoalSheet (Drawer), profile integration (editable own, read-only others),
federation toggle in settings (Switch).
Classic HTML: glassmorphic goal card on profile, Frutiger Aero styling.
Progress computed from existing reviews — backwards compatible.

crates/application/src/users/update_settings.rs

@@ -0,0 +1,15 @@
+use domain::{errors::DomainError, value_objects::UserId};
+
+use crate::context::AppContext;
+
+pub struct UpdateUserSettingsCommand {
+    pub user_id: uuid::Uuid,
+    pub federate_goals: bool,
+}
+
+pub async fn execute(ctx: &AppContext, cmd: UpdateUserSettingsCommand) -> Result<(), DomainError> {
+    let uid = UserId::from_uuid(cmd.user_id);
+    let mut settings = ctx.repos.user_settings.get(&uid).await?;
+    settings.set_federate_goals(cmd.federate_goals);
+    ctx.repos.user_settings.save(&settings).await
+}