Improve WebUI UX with tooltips, auto-fill and button visibility

- Add informational tooltips to all configuration fields
- Reorder tabs: Frigate first, then Go2RTC, then URL
- Hide Copy/Download buttons on Frigate tab until config is generated
- Auto-fill username field with "admin" as default value
- Smart pre-fill network address based on server IP (first 3 octets)
- Add tooltips for Main Stream, Sub Stream, and all buttons
- Improve user guidance throughout the configuration flow

webui/web/css/main.css

@@ -774,6 +774,9 @@ body {
 }
 
 .stream-label {
+    display: flex;
+    align-items: center;
+    gap: var(--space-2);
     font-size: var(--text-xs);
     font-weight: 600;
     color: var(--text-tertiary);
@@ -1032,6 +1035,81 @@ body {
     transform: translateY(0);
 }
 
+/* Button with tooltip wrapper */
+.button-with-tooltip {
+    position: relative;
+    width: 100%;
+}
+
+.button-with-tooltip .btn-generate {
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    gap: var(--space-2);
+}
+
+/* Button with tooltip in secondary-actions */
+.secondary-actions .button-with-tooltip {
+    flex: 1.2;
+    width: auto;
+}
+
+.secondary-actions .button-with-tooltip .btn {
+    width: 100%;
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    gap: var(--space-2);
+}
+
+.secondary-actions .button-with-tooltip:last-child {
+    flex: 0.8;
+}
+
+/* Info icon inside button */
+.info-icon-button {
+    position: relative;
+    display: inline-flex;
+    align-items: center;
+    justify-content: center;
+    width: 18px;
+    height: 18px;
+    cursor: help;
+    color: rgba(255, 255, 255, 0.7);
+    transition: color var(--transition-fast);
+}
+
+.info-icon-button:hover {
+    color: rgba(255, 255, 255, 1);
+}
+
+.info-icon-button svg {
+    width: 18px;
+    height: 18px;
+}
+
+/* Info icon inside outline button */
+.info-icon-button-outline {
+    position: relative;
+    display: inline-flex;
+    align-items: center;
+    justify-content: center;
+    width: 18px;
+    height: 18px;
+    cursor: help;
+    color: var(--text-tertiary);
+    transition: color var(--transition-fast);
+}
+
+.info-icon-button-outline:hover {
+    color: var(--purple-primary);
+}
+
+.info-icon-button-outline svg {
+    width: 18px;
+    height: 18px;
+}
+
 .frigate-output-section {
     margin-top: var(--space-6);
     padding-top: var(--space-6);