refactor(peer): split local library and operation UI events

Replace the `a9f9845` local-update dedup cache with explicit peer event
semantics. Local scans now emit `LocalLibraryChanged` when the library changes,
while operation mutations emit `ActiveOperationsChanged` from the mutation
path. Tauri keeps joining those facts into the existing `games-list-updated`
payload, so the frontend contract stays stable.

This removes the cache/invalidation coupling between scan emission and
operation state. The remaining forced local snapshot is explicit: accepted game
directory changes can refresh the UI for an equivalent new path without sending
a peer library delta.

Operation guard cleanup and liveness cancellation now publish the same active
operation snapshot as normal command-handler transitions. The peer CLI JSONL
events follow the same split with `local-library-changed` and
`active-operations-changed`.

Test Plan:
- `just fmt`
- `CARGO_BUILD_RUSTC_WRAPPER= just test`
- `CARGO_BUILD_RUSTC_WRAPPER= just clippy`
- `git diff --check`

Refs: CLEAN_CODE_PLAN_1.md

crates/lanspread-peer-cli/src/main.rs

@@ -359,19 +359,17 @@ async fn update_state_from_event(shared: &SharedState, event: PeerEvent) -> (&'s
             shared.state.write().await.remote_games = games.clone();
             ("list-games", json!({ "games": games }))
         }
-        PeerEvent::LocalGamesUpdated {
-            games,
-            active_operations,
-        } => {
+        PeerEvent::LocalLibraryChanged { games } => {
             let mut state = shared.state.write().await;
             state.local_games.clone_from(&games);
+            ("local-library-changed", json!({ "games": games }))
+        }
+        PeerEvent::ActiveOperationsChanged { active_operations } => {
+            let mut state = shared.state.write().await;
             state.active_operations.clone_from(&active_operations);
             (
-                "local-games-updated",
-                json!({
-                    "games": games,
-                    "active_operations": active_operations_json(&active_operations),
-                }),
+                "active-operations-changed",
+                json!({ "active_operations": active_operations_json(&active_operations) }),
             )
         }
         PeerEvent::GotGameFiles {