feat: add clipboard history for code snippets

Implements issue #25 - Clipboard History feature that tracks copied
code snippets with language detection, search, and filtering.

Backend (Rust):
- New clipboard.rs module with persistent storage via tauri-plugin-store
- Commands: capture, list, delete, toggle pin, clear, search, update language
- Auto-deduplication and max history size (100 entries)
- Pinned entries stay at top and persist through clear

Frontend (Svelte/TypeScript):
- Clipboard store with filtering, search, and language detection
- ClipboardHistoryPanel component with search, language filter, pin/delete
- Clipboard button added to InputBar next to Snippets/Actions
- Auto-capture from code block copy buttons
- Auto-capture from manual text selection in terminal
- Insert snippets directly into input field

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/lib/components/InputBar.svelte

@@ -7,6 +7,7 @@
   import { characterState } from "$lib/stores/character";
   import { handleNewUserMessage } from "$lib/notifications/rules";
   import { setSkipNextGreeting } from "$lib/tauri";
+  import { clipboardStore } from "$lib/stores/clipboard";
   import {
     setShouldRestoreHistory,
     setSavedHistory,
@@ -27,6 +28,7 @@
   import AttachmentPreview from "$lib/components/AttachmentPreview.svelte";
   import SnippetLibraryPanel from "$lib/components/SnippetLibraryPanel.svelte";
   import QuickActionsPanel from "$lib/components/QuickActionsPanel.svelte";
+  import ClipboardHistoryPanel from "$lib/components/ClipboardHistoryPanel.svelte";
   import type { Attachment } from "$lib/types/messages";
 
   const INPUT_HISTORY_KEY = "hikari-input-history";
@@ -43,6 +45,7 @@
   let isDragging = $state(false);
   let showSnippetLibrary = $state(false);
   let showQuickActions = $state(false);
+  let showClipboardHistory = $state(false);
 
   // Input history state
   let inputHistory = $state<string[]>([]);
@@ -504,6 +507,15 @@ User: ${formattedMessage}`;
     const items = event.clipboardData?.items;
     let handledFile = false;
 
+    // Also capture text content to clipboard history
+    const textContent = event.clipboardData?.getData("text/plain");
+    if (textContent && textContent.trim().length > 0) {
+      // Only capture multi-line or longer text (likely code snippets)
+      if (textContent.includes("\n") || textContent.length > 50) {
+        clipboardStore.captureClipboard(textContent, null, "Pasted into chat");
+      }
+    }
+
     if (items && items.length > 0) {
       for (const item of items) {
         if (item.kind === "file") {
@@ -631,6 +643,16 @@ User: ${formattedMessage}`;
     userHasTyped = true;
   }
 
+  function handleClipboardInsert(content: string): void {
+    // Insert clipboard content at cursor position or append to input
+    if (inputValue.trim()) {
+      inputValue = inputValue + "\n\n" + content;
+    } else {
+      inputValue = content;
+    }
+    userHasTyped = true;
+  }
+
   async function handleQuickAction(prompt: string): Promise<void> {
     // Quick actions send the prompt directly
     if (!isConnected || isSubmitting) return;
@@ -787,6 +809,27 @@ User: ${formattedMessage}`;
       </svg>
       <span>Snippets</span>
     </button>
+    <button
+      type="button"
+      onclick={() => (showClipboardHistory = true)}
+      class="control-button"
+      title="Clipboard History"
+    >
+      <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="M9 5H7a2 2 0 00-2 2v12a2 2 0 002 2h10a2 2 0 002-2V7a2 2 0 00-2-2h-2" />
+        <rect x="9" y="3" width="6" height="4" rx="1" />
+      </svg>
+      <span>Clipboard</span>
+    </button>
   </div>
 
   <div class="input-row">
@@ -870,9 +913,14 @@ User: ${formattedMessage}`;
 {/if}
 
 {#if showQuickActions}
-  <QuickActionsPanel
-    onClose={() => (showQuickActions = false)}
-    onAction={handleQuickAction}
+  <QuickActionsPanel onClose={() => (showQuickActions = false)} onAction={handleQuickAction} />
+{/if}
+
+{#if showClipboardHistory}
+  <ClipboardHistoryPanel
+    isOpen={showClipboardHistory}
+    onClose={() => (showClipboardHistory = false)}
+    onInsert={handleClipboardInsert}
   />
 {/if}
 
@@ -1043,6 +1091,8 @@ User: ${formattedMessage}`;
 
   .trans-gradient-button:hover:not(:disabled) {
     filter: brightness(1.1);
-    box-shadow: 0 0 20px rgba(91, 206, 250, 0.4), 0 0 30px rgba(245, 169, 184, 0.3);
+    box-shadow:
+      0 0 20px rgba(91, 206, 250, 0.4),
+      0 0 30px rgba(245, 169, 184, 0.3);
   }
 </style>