feat(meeting): opt-in process-list reminder when a meeting app starts

Default off. When on, the layout polls detect_meeting_processes every 15s
with the user's app-name patterns. On a fresh match (edge-triggered — no
re-toast until the app goes away and comes back) we fire a reminder toast
that tells the user which meeting app appeared and their global hotkey. We
never start recording on this signal; the ideology rule says the user
decides. The signal is a single channel: process list match only — no mic
activity heuristic, no calendar.

Backend adds kon_core::process_watch::{list_running_process_names,
match_meeting_patterns} over sysinfo, exposed to the frontend as the
detect_meeting_processes Tauri command.

Settings ships two new fields — meetingAutoCapture (bool) and
meetingAutoCaptureApps (string[]) — with a comma-separated input in the
Output section. Default app list is ["zoom", "teams"], user-editable.

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

src/routes/+layout.svelte

@@ -287,12 +287,44 @@
         }
       })
       .catch(() => { /* update check failure must not affect the app */ });
+
+    // Meeting auto-capture: poll the process list and toast when a match
+    // appears (edge-triggered — no repeat toasts until the app goes away
+    // and comes back). We never start recording from this signal; the
+    // user decides whether to hit the hotkey.
+    if (tauriRuntimeAvailable) {
+      let previous: Set<string> = new Set();
+      meetingCapturePoller = window.setInterval(async () => {
+        if (!settings.meetingAutoCapture) { previous = new Set(); return; }
+        const patterns = settings.meetingAutoCaptureApps;
+        if (!Array.isArray(patterns) || patterns.length === 0) return;
+        try {
+          const matches: string[] = await invoke("detect_meeting_processes", { patterns });
+          const current = new Set(matches);
+          for (const match of matches) {
+            if (!previous.has(match)) {
+              toasts.info(
+                `${match[0].toUpperCase()}${match.slice(1)} detected`,
+                `Press ${settings.globalHotkey} to start recording.`,
+              );
+            }
+          }
+          previous = current;
+        } catch { /* ignore — backend may be mid-restart */ }
+      }, 15000);
+    }
   });
 
+  let meetingCapturePoller: number | null = null;
+
   onDestroy(() => {
     window.removeEventListener("resize", handleResize);
     if (onWindowError) window.removeEventListener("error", onWindowError);
     if (onUnhandledRejection) window.removeEventListener("unhandledrejection", onUnhandledRejection);
+    if (meetingCapturePoller !== null) {
+      window.clearInterval(meetingCapturePoller);
+      meetingCapturePoller = null;
+    }
     if (!tauriRuntimeAvailable) {
       return;
     }