test: add test cases for plugins with parameters

Add new test scenarios (Test 10-13) to launch-test.html that include
plugins with parameters to test the expansion twisty and form fields:

- Test 10: Single plugin with string, number, and boolean parameters
- Test 11: Multiple plugins each with their own parameters
- Test 12: Mixed scenario with plugins with and without parameters
- Test 13: Plugin with empty string parameter (user must fill in)

These tests exercise the parameter form UI that was not covered by the
existing test cases which only used plugins without parameters.

Co-authored-by: openhands <openhands@all-hands.dev>

.pr/launch-test.html

@@ -289,6 +289,65 @@
     <button onclick="runTest6()">Launch Test</button>
   </div>
 
+  <h2>⚙️ Plugin Parameters (Form Fields)</h2>
+
+  <div class="test-case" id="test10">
+    <h3>Test 10: Single Plugin with Parameters</h3>
+    <p><strong>Plugin:</strong> aws-deploy (simulated)</p>
+    <p><strong>Parameters:</strong></p>
+    <ul>
+      <li><code>region</code> (string): "us-west-2"</li>
+      <li><code>timeout</code> (number): 30</li>
+      <li><code>debug</code> (boolean): false</li>
+    </ul>
+    <div class="expected">
+      <strong>Expected:</strong> Modal shows plugin with expandable section (expanded by default). Form fields appear for each parameter: text input for region, number input for timeout, checkbox for debug. Values are pre-filled with defaults.
+    </div>
+    <button onclick="runTest10()">Launch Test</button>
+  </div>
+
+  <div class="test-case" id="test11">
+    <h3>Test 11: Multiple Plugins with Parameters</h3>
+    <p><strong>Plugins:</strong></p>
+    <ul>
+      <li><code>data-pipeline</code> with params: source_bucket (string), batch_size (number)</li>
+      <li><code>transformer</code> with params: format (string), compress (boolean)</li>
+    </ul>
+    <div class="expected">
+      <strong>Expected:</strong> Modal shows two expandable sections (both expanded by default), each with their own form fields. User can collapse/expand each section independently.
+    </div>
+    <button onclick="runTest11()">Launch Test</button>
+  </div>
+
+  <div class="test-case" id="test12">
+    <h3>Test 12: Mixed - Plugins With and Without Parameters</h3>
+    <p><strong>Plugins:</strong></p>
+    <ul>
+      <li><code>aws-deploy</code> WITH params: region, timeout, debug</li>
+      <li><code>logging-plugin</code> WITHOUT params</li>
+      <li><code>metrics-plugin</code> WITHOUT params</li>
+    </ul>
+    <div class="expected">
+      <strong>Expected:</strong> Modal shows aws-deploy as expandable section with form fields. Below it, "Additional Plugins" collapsible section lists logging-plugin and metrics-plugin without form fields.
+    </div>
+    <button onclick="runTest12()">Launch Test</button>
+  </div>
+
+  <div class="test-case" id="test13">
+    <h3>Test 13: Plugin with Empty String Parameters</h3>
+    <p><strong>Plugin:</strong> api-connector</p>
+    <p><strong>Parameters:</strong></p>
+    <ul>
+      <li><code>api_key</code> (string): "" (empty - user must fill in)</li>
+      <li><code>endpoint</code> (string): "https://api.example.com"</li>
+      <li><code>rate_limit</code> (number): 100</li>
+    </ul>
+    <div class="expected">
+      <strong>Expected:</strong> Modal shows form fields with api_key empty, endpoint pre-filled, rate_limit set to 100. User can edit all fields before starting.
+    </div>
+    <button onclick="runTest13()">Launch Test</button>
+  </div>
+
   <h2 class="error-heading">❌ Error Scenarios</h2>
 
   <div class="test-case error-case" id="test7">
@@ -418,6 +477,83 @@
       const maliciousMessage = '<scr' + 'ipt>alert("xss")<\/scr' + 'ipt>This text should appear safely';
       openLaunchUrl(`?plugins=${encodePlugins(plugins)}&message=${encodeURIComponent(maliciousMessage)}`);
     }
+
+    // Test 10: Single plugin with parameters (shows form fields)
+    function runTest10() {
+      const plugins = [{
+        source: "github:example/aws-deploy",
+        repo_path: "plugins/aws-deploy",
+        parameters: {
+          region: "us-west-2",
+          timeout: 30,
+          debug: false
+        }
+      }];
+      openLaunchUrl(`?plugins=${encodePlugins(plugins)}`);
+    }
+
+    // Test 11: Multiple plugins with parameters
+    function runTest11() {
+      const plugins = [
+        {
+          source: "github:example/data-pipeline",
+          repo_path: "plugins/data-pipeline",
+          parameters: {
+            source_bucket: "my-data-bucket",
+            batch_size: 100
+          }
+        },
+        {
+          source: "github:example/transformer",
+          repo_path: "plugins/transformer",
+          parameters: {
+            format: "json",
+            compress: true
+          }
+        }
+      ];
+      openLaunchUrl(`?plugins=${encodePlugins(plugins)}`);
+    }
+
+    // Test 12: Mixed - plugins with and without parameters
+    function runTest12() {
+      const plugins = [
+        {
+          source: "github:example/aws-deploy",
+          repo_path: "plugins/aws-deploy",
+          parameters: {
+            region: "us-east-1",
+            timeout: 60,
+            debug: true
+          }
+        },
+        {
+          source: "github:example/logging-plugin",
+          repo_path: "plugins/logging"
+          // No parameters
+        },
+        {
+          source: "github:example/metrics-plugin",
+          repo_path: "plugins/metrics"
+          // No parameters
+        }
+      ];
+      openLaunchUrl(`?plugins=${encodePlugins(plugins)}`);
+    }
+
+    // Test 13: Plugin with empty string parameters (user must fill in)
+    function runTest13() {
+      const plugins = [{
+        source: "github:example/api-connector",
+        repo_path: "plugins/api-connector",
+        parameters: {
+          api_key: "",
+          endpoint: "https://api.example.com",
+          rate_limit: 100
+        }
+      }];
+      openLaunchUrl(`?plugins=${encodePlugins(plugins)}`);
+    }
   </script>
 </body>
 </html>