Probe both chat renderers via -Dprobe.renderer launch property

Both the browser-based (HTML) and the seasoned StyledText renderers ship
behind the useBrowserBasedChatRenderer preference, so both need probe
coverage. Select the renderer per launch instead of hardcoding it.

- ProbeRunner: read -Dprobe.renderer (browser | styledtext) and set
  USE_BROWSER_BASED_CHAT_RENDERER accordingly. Default styledtext matches the
  production default, so plain runs still exercise the SWT widget tree.
- chat-send-receive-001.json: restored to the strong StyledText widget-tree
  assertions (user-turn, copilot-turn, model-info-label) for the default
  renderer.
- chat-send-receive-browser-001.json (new): browser-renderer variant that
  asserts the Browser widget exists, then uses sleep + screenshot because the
  HTML DOM is opaque to SWTBot widget locators.
- REFERENCE.md: document the -Dprobe.renderer property and the two-probe
  workflow for covering both renderers.

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

Author: travkin79

.github/skills/ui-action/REFERENCE.md

@@ -34,6 +34,29 @@ The module-only shortcut can fail dependency resolution or reuse stale bundles,
 especially after source edits. If widget markers or other code changes appear to
 be ignored, run the root `clean verify` command.
 
+### Selecting the chat renderer
+
+The plugin ships two chat renderers behind the `useBrowserBasedChatRenderer`
+preference, and probes can target either one via the `-Dprobe.renderer` launch
+property (read once by `ProbeRunner` before the ChatView opens):
+
+- omit it, or pass `-Dprobe.renderer=styledtext`, to run against the seasoned
+  StyledText renderer (the production default). These probes assert the SWT
+  widget tree (`user-turn`, `copilot-turn`, `model-info-label`).
+- pass `-Dprobe.renderer=browser` to run against the browser-based (HTML)
+  renderer. Its conversation content lives in an SWT `Browser` DOM that is opaque
+  to SWTBot widget locators, so those probes assert the `Browser` widget exists
+  and fall back to `sleep` + `screenshot` for visual verification.
+
+Because the renderer is chosen per launch, cover both by running the two probes:
+
+```bash
+# StyledText renderer (default)
+./mvnw clean verify -Dprobe.script=probe-scripts/chat-send-receive-001.json
+# Browser renderer
+./mvnw clean verify -Dprobe.script=probe-scripts/chat-send-receive-browser-001.json -Dprobe.renderer=browser
+```
+
 Platform notes:
 
 - Linux headless: prefix the command with `xvfb-run -a`.

com.microsoft.copilot.eclipse.swtbot.test/probe-scripts/chat-send-receive-browser-001.json

@@ -0,0 +1,44 @@
+[
+  { "action": "waitForIdle" },
+  { "action": "screenshot", "id": "01-startup" },
+
+  { "action": "showView", "idRef": "com.microsoft.copilot.eclipse.ui.chat.ChatView" },
+  { "action": "waitForIdle" },
+  { "action": "screenshot", "id": "02-chat-open" },
+
+  { "action": "assertExists",
+    "locator": { "by": "viewId", "id": "com.microsoft.copilot.eclipse.ui.chat.ChatView" } },
+
+  { "action": "waitFor",
+    "locator": { "by": "widgetClass", "value": "Browser" },
+    "timeoutSec": 30 },
+
+  { "action": "waitFor",
+    "locator": { "by": "styledText" },
+    "timeoutSec": 30 },
+
+  { "action": "click", "locator": { "by": "styledText" } },
+  { "action": "clearElement", "locator": { "by": "styledText" } },
+  { "action": "typeIn", "locator": { "by": "styledText" }, "text": "hello" },
+  { "action": "screenshot", "id": "03-typed" },
+
+  { "action": "dumpUi",     "id": "03b-pre-model-poll" },
+  { "action": "screenshot", "id": "03c-pre-model-poll" },
+
+  { "action": "waitForMethod",
+    "locator": { "by": "widgetId", "value": "model-picker" },
+    "method": "getSelectedItemId",
+    "timeoutSec": 60 },
+
+  { "action": "waitFor",
+    "locator": { "by": "buttonWithTooltip", "tooltip": "Send" },
+    "timeoutSec": 30 },
+  { "action": "click", "locator": { "by": "buttonWithTooltip", "tooltip": "Send" } },
+
+  { "action": "sleep", "timeoutSec": 5 },
+  { "action": "screenshot", "id": "04-user-message-sent" },
+
+  { "action": "sleep", "timeoutSec": 90 },
+  { "action": "screenshot", "id": "05-agent-response" },
+  { "action": "dumpUi", "id": "06-final" }
+]

com.microsoft.copilot.eclipse.swtbot.test/src/com/microsoft/copilot/eclipse/swtbot/test/probe/ProbeRunner.java

@@ -48,6 +48,7 @@
 @RunWith(SWTBotJunit4ClassRunner.class)
 public class ProbeRunner {
   private static final String SYSPROP = "probe.script";
+  private static final String RENDERER_SYSPROP = "probe.renderer";
   private static final Path RESULTS_DIR = Paths.get("target", "probe-results");
   private static final String UI_BUNDLE_ID = "com.microsoft.copilot.eclipse.ui";
 
@@ -77,6 +78,13 @@ private static void suppressNuisancePreferences() {
       prefs.putBoolean(Constants.AUTO_SHOW_WHAT_IS_NEW, false);
       prefs.put(Constants.LAST_USED_COPILOT_PLUGIN_VERSION, currentUiBundleMajorMinor());
       prefs.putBoolean(Constants.SUPPRESS_TERMINAL_DEPENDENCY_DIALOG, true);
+      // Select the chat renderer per launch so the same probe flow can be run against both
+      // renderers: pass -Dprobe.renderer=browser for the browser-based (HTML) renderer, or
+      // omit it (or -Dprobe.renderer=styledtext) for the seasoned StyledText renderer. The
+      // default matches production (StyledText), so plain runs exercise the SWT widget tree.
+      boolean useBrowserRenderer =
+          "browser".equalsIgnoreCase(System.getProperty(RENDERER_SYSPROP, "styledtext"));
+      prefs.putBoolean(Constants.USE_BROWSER_BASED_CHAT_RENDERER, useBrowserRenderer);
       prefs.flush();
     } catch (BackingStoreException | RuntimeException e) {
       System.err.println("[ProbeRunner] Failed to preset nuisance-dialog preferences: " + e);