Add help dialog and tooltip indicators throughout the UI

- Add circled ? help button in TopBar that opens a dialog with HOW-TO-USE.md content
- Create reusable Tooltip component with viewport-aware positioning
- Add 32 tooltip indicators across project config and settings panels
- Covers backend selection, Bedrock/Ollama/LiteLLM fields, Docker, AWS, MCP, and more

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/src/index.css

@@ -53,3 +53,135 @@ body {
   to   { opacity: 1; transform: translate(-50%, 0); }
 }
 .animate-slide-down { animation: slide-down 0.2s ease-out; }
+
+/* Help dialog content styles */
+.help-content {
+  font-size: 0.8125rem;
+  line-height: 1.6;
+  color: var(--text-primary);
+}
+
+.help-content .help-h1 {
+  font-size: 1.5rem;
+  font-weight: 700;
+  margin: 0 0 1rem 0;
+  color: var(--text-primary);
+}
+
+.help-content .help-h2 {
+  font-size: 1.15rem;
+  font-weight: 600;
+  margin: 1.5rem 0 0.75rem 0;
+  padding-bottom: 0.375rem;
+  border-bottom: 1px solid var(--border-color);
+  color: var(--text-primary);
+}
+
+.help-content .help-h3 {
+  font-size: 0.95rem;
+  font-weight: 600;
+  margin: 1.25rem 0 0.5rem 0;
+  color: var(--text-primary);
+}
+
+.help-content .help-h4 {
+  font-size: 0.875rem;
+  font-weight: 600;
+  margin: 1rem 0 0.375rem 0;
+  color: var(--text-secondary);
+}
+
+.help-content .help-p {
+  margin: 0.5rem 0;
+}
+
+.help-content .help-ul,
+.help-content .help-ol {
+  margin: 0.5rem 0;
+  padding-left: 1.5rem;
+}
+
+.help-content .help-ul {
+  list-style-type: disc;
+}
+
+.help-content .help-ol {
+  list-style-type: decimal;
+}
+
+.help-content .help-ul li,
+.help-content .help-ol li {
+  margin: 0.25rem 0;
+}
+
+.help-content .help-code-block {
+  display: block;
+  background: var(--bg-primary);
+  border: 1px solid var(--border-color);
+  border-radius: 6px;
+  padding: 0.75rem 1rem;
+  margin: 0.5rem 0;
+  overflow-x: auto;
+  font-family: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
+  font-size: 0.75rem;
+  line-height: 1.5;
+  white-space: pre;
+}
+
+.help-content .help-inline-code {
+  background: var(--bg-tertiary);
+  border: 1px solid var(--border-color);
+  border-radius: 3px;
+  padding: 0.125rem 0.375rem;
+  font-family: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
+  font-size: 0.75rem;
+}
+
+.help-content .help-table {
+  width: 100%;
+  border-collapse: collapse;
+  margin: 0.5rem 0;
+  font-size: 0.75rem;
+}
+
+.help-content .help-table th,
+.help-content .help-table td {
+  border: 1px solid var(--border-color);
+  padding: 0.375rem 0.625rem;
+  text-align: left;
+}
+
+.help-content .help-table th {
+  background: var(--bg-tertiary);
+  font-weight: 600;
+}
+
+.help-content .help-table td {
+  background: var(--bg-primary);
+}
+
+.help-content .help-blockquote {
+  border-left: 3px solid var(--accent);
+  background: var(--bg-primary);
+  margin: 0.5rem 0;
+  padding: 0.5rem 0.75rem;
+  border-radius: 0 4px 4px 0;
+  color: var(--text-secondary);
+  font-size: 0.75rem;
+}
+
+.help-content .help-hr {
+  border: none;
+  border-top: 1px solid var(--border-color);
+  margin: 1.5rem 0;
+}
+
+.help-content .help-link {
+  color: var(--accent);
+  text-decoration: none;
+}
+
+.help-content .help-link:hover {
+  color: var(--accent-hover);
+  text-decoration: underline;
+}