feat: add automatic greeting upon connection (#42)

### Explanation

_No response_

### Issue

Closes #23

### Attestations

- [ ] I have read and agree to the [Code of Conduct](https://docs.nhcarrigan.com/community/coc/)
- [ ] I have read and agree to the [Community Guidelines](https://docs.nhcarrigan.com/community/guide/).
- [ ] My contribution complies with the [Contributor Covenant](https://docs.nhcarrigan.com/dev/covenant/).

### Dependencies

- [ ] I have pinned the dependencies to a specific patch version.

### Style

- [ ] I have run the linter and resolved any errors.
- [ ] My pull request uses an appropriate title, matching the conventional commit standards.
- [ ] My scope of feat/fix/chore/etc. correctly matches the nature of changes in my pull request.

### Tests

- [ ] My contribution adds new code, and I have added tests to cover it.
- [ ] My contribution modifies existing code, and I have updated the tests to reflect these changes.
- [ ] All new and existing tests pass locally with my changes.
- [ ] Code coverage remains at or above the configured threshold.

### Documentation

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### Versioning

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Reviewed-on: #42
Co-authored-by: Naomi Carrigan <commits@nhcarrigan.com>
Co-committed-by: Naomi Carrigan <commits@nhcarrigan.com>

src/lib/tauri.ts

@@ -1,6 +1,8 @@
 import { listen } from "@tauri-apps/api/event";
+import { invoke } from "@tauri-apps/api/core";
 import { claudeStore } from "$lib/stores/claude";
 import { characterState } from "$lib/stores/character";
+import { configStore } from "$lib/stores/config";
 import type { ConnectionStatus, PermissionPromptEvent } from "$lib/types/messages";
 import type { CharacterState } from "$lib/types/states";
 
@@ -9,6 +11,46 @@ interface StateChangePayload {
   tool_name: string | null;
 }
 
+function getTimeOfDay(): string {
+  const hour = new Date().getHours();
+
+  if (hour >= 5 && hour < 12) {
+    return "morning";
+  } else if (hour >= 12 && hour < 17) {
+    return "afternoon";
+  } else if (hour >= 17 && hour < 21) {
+    return "evening";
+  } else {
+    return "late night";
+  }
+}
+
+function generateGreetingPrompt(): string {
+  const timeOfDay = getTimeOfDay();
+  return `[System: A new session has started. It's currently ${timeOfDay}. Please greet the user warmly and briefly. Keep it short - just 1-2 sentences.]`;
+}
+
+async function sendGreeting() {
+  const config = configStore.getConfig();
+
+  if (!config.greeting_enabled) {
+    return;
+  }
+
+  const greetingPrompt = config.greeting_custom_prompt?.trim() || generateGreetingPrompt();
+
+  // Don't show the system prompt in the UI - just trigger Claude to respond
+  characterState.setState("thinking");
+
+  try {
+    await invoke("send_prompt", { message: greetingPrompt });
+  } catch (error) {
+    console.error("Failed to send greeting:", error);
+    claudeStore.addLine("error", `Failed to send greeting: ${error}`);
+    characterState.setTemporaryState("error", 3000);
+  }
+}
+
 interface OutputPayload {
   line_type: string;
   content: string;
@@ -16,13 +58,15 @@ interface OutputPayload {
 }
 
 export async function initializeTauriListeners() {
-  await listen<string>("claude:connection", (event) => {
+  await listen<string>("claude:connection", async (event) => {
     const status = event.payload as ConnectionStatus;
     claudeStore.setConnectionStatus(status);
 
     if (status === "connected") {
       claudeStore.addLine("system", "Connected to Claude Code");
       characterState.setState("idle");
+      // Send greeting when connection is established
+      await sendGreeting();
     } else if (status === "disconnected") {
       claudeStore.addLine("system", "Disconnected from Claude Code");
       characterState.setState("idle");