fix: improve interrupt and disconnect message descriptions

Messages now indicate how the interrupt was triggered (keyboard shortcut,
stop button, or unexpected crash) so the cause is immediately clear.

src/lib/components/CompactMode.svelte

@@ -135,7 +135,7 @@
       setSkipNextGreeting(true);
 
       await invoke("interrupt_claude", { conversationId });
-      claudeStore.addLine("system", "Interrupted");
+      claudeStore.addLine("system", "Process interrupted via stop button");
       characterState.setState("idle");
     } catch (error) {
       console.error("Failed to interrupt:", error);

src/lib/components/InputBar.svelte

@@ -343,7 +343,7 @@ User: ${formattedMessage}`;
         throw new Error("No active conversation");
       }
       await invoke("interrupt_claude", { conversationId });
-      claudeStore.addLine("system", "Process interrupted - reconnecting...");
+      claudeStore.addLine("system", "Process interrupted via stop button — reconnecting...");
       characterState.setState("idle");
 
       // Show connecting status while we reconnect

src/lib/tauri.ts

@@ -221,7 +221,7 @@ export async function initializeTauriListeners() {
         claudeStore.addLineToConversation(
           targetConversationId,
           "system",
-          "Disconnected from Claude Code"
+          "Disconnected from Claude Code unexpectedly — the process may have crashed or been stopped by the system"
         );
 
         // Clear todos on real disconnect (not on reconnects for permissions)

src/routes/+page.svelte

@@ -337,7 +337,7 @@
       setSkipNextGreeting(true);
 
       await invoke("interrupt_claude", { conversationId });
-      claudeStore.addLine("system", "Process interrupted");
+      claudeStore.addLine("system", "Process interrupted by keyboard shortcut (Ctrl+C)");
     } catch (error) {
       console.error("Failed to interrupt:", error);
     }