Add project save/load and improve AI chat formatting

Project persistence:
- save_project_transcript command: persists segments, speakers, words to SQLite
- load_project_transcript command: loads full transcript with nested words
- delete_project command: soft-delete projects
- Auto-save after pipeline completes (named from filename)
- Project dropdown in header to switch between saved transcripts
- Projects load audio, segments, and speakers from database

AI chat improvements:
- Markdown rendering in assistant messages (headers, lists, bold, italic, code)
- Better message spacing and visual distinction (border-left accents)
- Styled markdown elements matching dark theme
- Improved empty state and quick action button sizing

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/lib/components/AIChatPanel.svelte

@@ -88,6 +88,88 @@
     messages = [];
   }
 
+  function formatMarkdown(text: string): string {
+    // Split into lines for block-level processing
+    const lines = text.split('\n');
+    const result: string[] = [];
+    let inList = false;
+
+    for (let i = 0; i < lines.length; i++) {
+      let line = lines[i];
+
+      // Headers
+      if (line.startsWith('### ')) {
+        if (inList) { result.push('</ul>'); inList = false; }
+        const content = applyInlineFormatting(line.slice(4));
+        result.push(`<h4>${content}</h4>`);
+        continue;
+      }
+      if (line.startsWith('## ')) {
+        if (inList) { result.push('</ul>'); inList = false; }
+        const content = applyInlineFormatting(line.slice(3));
+        result.push(`<h3>${content}</h3>`);
+        continue;
+      }
+      if (line.startsWith('# ')) {
+        if (inList) { result.push('</ul>'); inList = false; }
+        const content = applyInlineFormatting(line.slice(2));
+        result.push(`<h2>${content}</h2>`);
+        continue;
+      }
+
+      // List items (- or *)
+      if (/^[\-\*] /.test(line)) {
+        if (!inList) { result.push('<ul>'); inList = true; }
+        const content = applyInlineFormatting(line.slice(2));
+        result.push(`<li>${content}</li>`);
+        continue;
+      }
+
+      // Numbered list items
+      if (/^\d+\.\s/.test(line)) {
+        if (!inList) { result.push('<ol>'); inList = true; }
+        const content = applyInlineFormatting(line.replace(/^\d+\.\s/, ''));
+        result.push(`<li>${content}</li>`);
+        continue;
+      }
+
+      // Non-list line: close any open list
+      if (inList) {
+        // Check if previous list was ordered or unordered
+        const lastOpen = result.findLast(r => r === '<ul>' || r === '<ol>');
+        result.push(lastOpen === '<ol>' ? '</ol>' : '</ul>');
+        inList = false;
+      }
+
+      // Empty line = paragraph break
+      if (line.trim() === '') {
+        result.push('<br>');
+        continue;
+      }
+
+      // Regular text line
+      result.push(applyInlineFormatting(line));
+    }
+
+    // Close any trailing open list
+    if (inList) {
+      const lastOpen = result.findLast(r => r === '<ul>' || r === '<ol>');
+      result.push(lastOpen === '<ol>' ? '</ol>' : '</ul>');
+    }
+
+    return result.join('\n');
+  }
+
+  function applyInlineFormatting(text: string): string {
+    // Code blocks (backtick) — process first to avoid conflicts
+    text = text.replace(/`([^`]+)`/g, '<code>$1</code>');
+    // Bold (**text**)
+    text = text.replace(/\*\*([^*]+)\*\*/g, '<strong>$1</strong>');
+    // Italic (*text*) — only single asterisks not already consumed by bold
+    text = text.replace(/\*([^*]+)\*/g, '<em>$1</em>');
+    return text;
+  }
+
   // Quick action buttons
   async function summarize() {
     inputText = 'Please summarize this transcript in bullet points.';
@@ -122,7 +204,11 @@
     {:else}
       {#each messages as msg}
         <div class="message {msg.role}">
-          <div class="message-content">{msg.content}</div>
+          {#if msg.role === 'assistant'}
+            <div class="message-content">{@html formatMarkdown(msg.content)}</div>
+          {:else}
+            <div class="message-content">{msg.content}</div>
+          {/if}
         </div>
       {/each}
       {#if isLoading}
@@ -192,47 +278,101 @@
   }
   .empty-state {
     text-align: center;
-    color: #666;
-    font-size: 0.8rem;
-    padding: 1rem 0;
+    color: #888;
+    font-size: 0.85rem;
+    padding: 2rem 1rem;
+  }
+  .empty-state p {
+    margin-bottom: 1rem;
   }
   .quick-actions {
     display: flex;
-    gap: 0.5rem;
+    gap: 0.75rem;
     justify-content: center;
-    margin-top: 0.5rem;
+    margin-top: 1rem;
   }
   .quick-btn {
     background: rgba(233, 69, 96, 0.15);
     border: 1px solid rgba(233, 69, 96, 0.3);
     color: #e94560;
-    padding: 0.3rem 0.6rem;
-    border-radius: 4px;
+    padding: 0.45rem 0.85rem;
+    border-radius: 6px;
     cursor: pointer;
-    font-size: 0.75rem;
+    font-size: 0.8rem;
+    transition: background 0.15s;
   }
   .quick-btn:hover {
     background: rgba(233, 69, 96, 0.25);
   }
   .message {
-    margin-bottom: 0.5rem;
-    padding: 0.5rem 0.75rem;
-    border-radius: 6px;
+    margin-bottom: 0.75rem;
+    padding: 0.75rem 1rem;
+    border-radius: 8px;
     font-size: 0.8rem;
-    line-height: 1.4;
+    line-height: 1.55;
   }
   .message.user {
     background: rgba(233, 69, 96, 0.15);
-    margin-left: 1rem;
+    border-left: 3px solid rgba(233, 69, 96, 0.4);
   }
   .message.assistant {
     background: rgba(255, 255, 255, 0.05);
-    margin-right: 1rem;
+    border-left: 3px solid rgba(255, 255, 255, 0.1);
   }
   .message.loading {
     opacity: 0.6;
     font-style: italic;
   }
+
+  /* Markdown styles inside assistant messages */
+  .message.assistant :global(h2) {
+    font-size: 1rem;
+    font-weight: 600;
+    margin: 0.6rem 0 0.3rem;
+    color: #f0f0f0;
+  }
+  .message.assistant :global(h3) {
+    font-size: 0.9rem;
+    font-weight: 600;
+    margin: 0.5rem 0 0.25rem;
+    color: #e8e8e8;
+  }
+  .message.assistant :global(h4) {
+    font-size: 0.85rem;
+    font-weight: 600;
+    margin: 0.4rem 0 0.2rem;
+    color: #e0e0e0;
+  }
+  .message.assistant :global(strong) {
+    color: #f0f0f0;
+    font-weight: 600;
+  }
+  .message.assistant :global(em) {
+    color: #ccc;
+    font-style: italic;
+  }
+  .message.assistant :global(code) {
+    background: rgba(0, 0, 0, 0.3);
+    color: #e94560;
+    padding: 0.1rem 0.35rem;
+    border-radius: 3px;
+    font-size: 0.75rem;
+    font-family: 'Fira Code', 'Cascadia Code', 'Consolas', monospace;
+  }
+  .message.assistant :global(ul),
+  .message.assistant :global(ol) {
+    margin: 0.35rem 0;
+    padding-left: 1.3rem;
+  }
+  .message.assistant :global(li) {
+    margin-bottom: 0.25rem;
+    line-height: 1.5;
+  }
+  .message.assistant :global(br) {
+    display: block;
+    content: '';
+    margin-top: 0.35rem;
+  }
   .chat-input {
     display: flex;
     gap: 0.5rem;