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/ingest.rs

@@ -0,0 +1,71 @@
+use chrono::Duration;
+use domain::{
+    errors::DomainError, events::DomainEvent, models::WatchEvent, ports::MediaServerParser,
+};
+
+use crate::{context::AppContext, integrations::commands::IngestWatchEventCommand};
+
+pub async fn execute(
+    ctx: &AppContext,
+    cmd: IngestWatchEventCommand,
+    parser: &dyn MediaServerParser,
+) -> Result<(), DomainError> {
+    let token_hash = super::generate_token::hash_token(&cmd.token);
+    let webhook_token = ctx
+        .repos
+        .webhook_token
+        .find_by_token_hash(&token_hash)
+        .await?
+        .ok_or_else(|| DomainError::Unauthorized("invalid webhook token".into()))?;
+
+    let _ = ctx
+        .repos
+        .webhook_token
+        .touch_last_used(webhook_token.id())
+        .await;
+
+    let parsed = match parser.parse_playback_event(&cmd.raw_payload)? {
+        Some(event) => event,
+        None => return Ok(()),
+    };
+
+    let external_metadata_id = parsed.tmdb_id.or(parsed.imdb_id);
+    let user_id = webhook_token.user_id().clone();
+
+    if let Some(ref ext_id) = external_metadata_id {
+        let one_hour_ago = chrono::Utc::now().naive_utc() - Duration::hours(1);
+        if ctx
+            .repos
+            .watch_event
+            .find_duplicate(&user_id, ext_id, one_hour_ago)
+            .await?
+        {
+            return Ok(());
+        }
+    }
+
+    let watched_at = chrono::Utc::now().naive_utc();
+    let event = WatchEvent::new(
+        user_id,
+        parsed.title,
+        parsed.year,
+        external_metadata_id,
+        cmd.source,
+        watched_at,
+        None,
+    );
+
+    ctx.repos.watch_event.save(&event).await?;
+
+    let _ = ctx
+        .services
+        .event_publisher
+        .publish(&DomainEvent::WatchEventIngested {
+            user_id: event.user_id().clone(),
+            title: event.title().to_string(),
+            source: event.source().to_string(),
+        })
+        .await;
+
+    Ok(())
+}