refactor: group use cases into DDD bounded contexts

Flat use_cases/ (44 files) + monolithic commands.rs/queries.rs
split into diary/, movies/, watchlist/, import/, auth/, users/,
integrations/, search/, person/, federation/ — each with own
commands.rs, queries.rs, and use case modules.

Inline tests extracted to sibling tests/ dirs.

crates/application/src/integrations/confirm.rs

@@ -0,0 +1,68 @@
+use domain::{
+    errors::DomainError,
+    models::WatchEventStatus,
+    value_objects::{UserId, WatchEventId},
+};
+
+use crate::{
+    context::AppContext,
+    diary::commands::{LogReviewCommand, MovieInput},
+    diary::log_review,
+    integrations::commands::ConfirmWatchEventsCommand,
+};
+
+pub async fn execute(ctx: &AppContext, cmd: ConfirmWatchEventsCommand) -> Result<u32, DomainError> {
+    let user_id = UserId::from_uuid(cmd.user_id);
+    let mut confirmed = 0u32;
+
+    for c in cmd.confirmations {
+        let event_id = WatchEventId::from_uuid(c.watch_event_id);
+        let event = ctx
+            .repos
+            .watch_event
+            .get_by_id(&event_id)
+            .await?
+            .ok_or_else(|| DomainError::NotFound(format!("WatchEvent {}", c.watch_event_id)))?;
+
+        if event.user_id() != &user_id {
+            return Err(DomainError::Unauthorized("not your watch event".into()));
+        }
+
+        let input = if let Some(movie_id) = event.movie_id() {
+            MovieInput {
+                movie_id: Some(movie_id.value()),
+                external_metadata_id: None,
+                manual_title: None,
+                manual_release_year: None,
+                manual_director: None,
+            }
+        } else {
+            MovieInput {
+                movie_id: None,
+                external_metadata_id: event.external_metadata_id().map(String::from),
+                manual_title: Some(event.title().to_string()),
+                manual_release_year: event.year(),
+                manual_director: None,
+            }
+        };
+
+        let review_cmd = LogReviewCommand {
+            user_id: cmd.user_id,
+            input,
+            rating: c.rating,
+            comment: c.comment,
+            watched_at: *event.watched_at(),
+        };
+
+        log_review::execute(ctx, review_cmd).await?;
+
+        ctx.repos
+            .watch_event
+            .update_status(&event_id, WatchEventStatus::Confirmed)
+            .await?;
+
+        confirmed += 1;
+    }
+
+    Ok(confirmed)
+}