style(clippy): clean up the two lints in phase3 new code

QC smoke sweep flagged two clippy -D warnings lints in code this branch
introduced:

- crates/core/src/process_watch.rs — collapsible_if on the meeting-pattern
  match loop, merged the two conditions with &&.
- crates/mcp/src/lib.rs — let-else on the id unwrap that short-circuits a
  notification, switched to ? since handle_message already returns Option.

All other clippy lints under -D warnings (audio/capture, hotkey/linux,
storage/file_storage, diagnostics, the duplicate-detection helpers in
live.rs) predate this branch and are out of scope.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

crates/core/src/process_watch.rs

@@ -33,10 +33,10 @@ pub fn match_meeting_patterns(process_names: &[String], patterns: &[String]) ->
         if needle.is_empty() {
             continue;
         }
-        if process_names.iter().any(|name| name.contains(&needle)) {
-            if !matches.iter().any(|existing| existing == &needle) {
-                matches.push(needle);
-            }
+        if process_names.iter().any(|name| name.contains(&needle))
+            && !matches.iter().any(|existing| existing == &needle)
+        {
+            matches.push(needle);
         }
     }
     matches