feat: new drafts feature and sound spam fix (#174)

## Summary

- **Saved Drafts feature**: Users can now save input content as drafts for later use, and manage them from a new panel
- **Sound spam fix**: The "Working on it!" sound no longer plays repeatedly when Claude makes multiple tool calls in a row

## Details

### Drafts feature
- Rust backend (`drafts.rs`) with `list_drafts`, `save_draft`, `delete_draft`, and `delete_all_drafts` commands, persisted to `hikari-drafts.json` via the Tauri Store plugin
- `draftsStore` wrapping all four commands with timestamp formatting
- `DraftPanel` overlay with insert, per-item two-step delete confirmation, delete-all with confirmation, empty state, and slide-in animation
- **Drafts** button in the top control row (pencil icon)
- **Save as Draft** floppy-disk icon button in the button wrapper (disabled when input is empty)

### Sound spam fix
- Root cause: `resetSoundState` was called on **every** `thinking` state transition, including mid-task transitions (`coding → thinking → coding`)
- Fix: only reset sound state when entering `thinking` from a clean-slate state (`idle`, `success`, or `error`) — states that genuinely mark the end of one task and the start of a new one

## Test plan
- [ ] Save a draft and verify it persists across app restarts
- [ ] Insert a draft and verify it populates the input
- [ ] Delete individual drafts and verify delete-all works
- [ ] Verify "Working on it!" plays once per user message regardless of how many tools are called

✨ This PR was created with help from Hikari~ 🌸

Reviewed-on: #174
Co-authored-by: Hikari <hikari@nhcarrigan.com>
Co-committed-by: Hikari <hikari@nhcarrigan.com>

src/lib/components/InputBar.svelte

@@ -34,7 +34,9 @@
   import SnippetLibraryPanel from "$lib/components/SnippetLibraryPanel.svelte";
   import QuickActionsPanel from "$lib/components/QuickActionsPanel.svelte";
   import ClipboardHistoryPanel from "$lib/components/ClipboardHistoryPanel.svelte";
+  import DraftPanel from "$lib/components/DraftPanel.svelte";
   import TextInputContextMenu from "$lib/components/TextInputContextMenu.svelte";
+  import { draftsStore } from "$lib/stores/drafts";
   import type { Attachment } from "$lib/types/messages";
 
   const INPUT_HISTORY_KEY = "hikari-input-history";
@@ -52,6 +54,7 @@
   let showSnippetLibrary = $state(false);
   let showQuickActions = $state(false);
   let showClipboardHistory = $state(false);
+  let showDraftPanel = $state(false);
   let streamerModeActive = $state(false);
 
   // Cost estimation for pre-submission display
@@ -175,6 +178,14 @@
     }
   });
 
+  function clearInput() {
+    inputValue = "";
+    const activeId = get(claudeStore.activeConversationId);
+    if (activeId) {
+      claudeStore.setDraftText(activeId, "");
+    }
+  }
+
   function handleInputChange() {
     // If input is empty, allow history navigation again
     // Otherwise, mark that user has manually typed
@@ -212,7 +223,7 @@
   async function executeSlashCommand(): Promise<boolean> {
     const { command, args } = parseSlashCommand(inputValue);
     if (command) {
-      inputValue = "";
+      clearInput();
       showCommandMenu = false;
       matchingCommands = [];
       await command.execute(args);
@@ -245,7 +256,7 @@
         "error",
         `Unknown command: ${message.split(" ")[0]}. Type /help for available commands.`
       );
-      inputValue = "";
+      clearInput();
       return;
     }
 
@@ -261,7 +272,7 @@
     userHasTyped = false;
 
     isSubmitting = true;
-    inputValue = "";
+    clearInput();
 
     // Capture attachments before clearing
     const currentAttachments = [...attachments];
@@ -720,6 +731,22 @@ User: ${formattedMessage}`;
     userHasTyped = true;
   }
 
+  function handleDraftInsert(content: string): void {
+    inputValue = content;
+    userHasTyped = true;
+    const activeId = get(claudeStore.activeConversationId);
+    if (activeId) {
+      claudeStore.setDraftText(activeId, content);
+    }
+  }
+
+  async function handleSaveAsDraft(): Promise<void> {
+    const content = inputValue.trim();
+    if (!content) return;
+    await draftsStore.saveDraft(content);
+    clearInput();
+  }
+
   function handleClipboardInsert(content: string): void {
     // Insert clipboard content at cursor position or append to input
     if (inputValue.trim()) {
@@ -936,6 +963,29 @@ User: ${formattedMessage}`;
       <span>Clipboard</span>
     </button>
 
+    <button
+      type="button"
+      onclick={() => (showDraftPanel = true)}
+      class="control-button"
+      title="Saved Drafts"
+    >
+      <svg
+        width="16"
+        height="16"
+        viewBox="0 0 24 24"
+        fill="none"
+        stroke="currentColor"
+        stroke-width="2"
+        stroke-linecap="round"
+        stroke-linejoin="round"
+      >
+        <path
+          d="M11 5H6a2 2 0 00-2 2v11a2 2 0 002 2h11a2 2 0 002-2v-5m-1.414-9.414a2 2 0 112.828 2.828L11.828 15H9v-2.828l8.586-8.586z"
+        />
+      </svg>
+      <span>Drafts</span>
+    </button>
+
     <CliVersion />
     <SystemClock />
   </div>
@@ -976,6 +1026,29 @@ User: ${formattedMessage}`;
         </div>
       {/if}
 
+      <button
+        type="button"
+        onclick={handleSaveAsDraft}
+        disabled={!inputValue.trim()}
+        class="attach-button"
+        title="Save as Draft"
+      >
+        <svg
+          width="20"
+          height="20"
+          viewBox="0 0 24 24"
+          fill="none"
+          stroke="currentColor"
+          stroke-width="2"
+          stroke-linecap="round"
+          stroke-linejoin="round"
+        >
+          <path d="M19 21H5a2 2 0 0 1-2-2V5a2 2 0 0 1 2-2h11l5 5v11a2 2 0 0 1-2 2z" />
+          <polyline points="17 21 17 13 7 13 7 21" />
+          <polyline points="7 3 7 8 15 8" />
+        </svg>
+      </button>
+
       <button type="button" onclick={handleFilePicker} class="attach-button" title="Attach files">
         <svg
           width="20"
@@ -1041,6 +1114,10 @@ User: ${formattedMessage}`;
   />
 {/if}
 
+{#if showDraftPanel}
+  <DraftPanel onClose={() => (showDraftPanel = false)} onInsert={handleDraftInsert} />
+{/if}
+
 {#if contextMenuShow && textareaElement}
   <TextInputContextMenu
     x={contextMenuX}