WiFiManager: stream info and wifi pages through DFTE.

Harden the root placeholder path, add direct render-isolation coverage, move simple status pages and /info onto request-scoped streamed templates, and switch /wifi to a streamed shell while keeping scan/form sections string-built for now.

test/test_wifimanager/test_main.cpp

@@ -32,6 +32,7 @@ TestCase tests[] = {
     TEST_ENTRY(test_get_config_portal_ssid),
     TEST_ENTRY(test_root_render_menu_state_transitions),
     TEST_ENTRY(test_root_render_snapshot_consistency),
+    TEST_ENTRY(test_root_render_interleaved_context_isolation),
     
     // Non-blocking tests
     TEST_ENTRY(test_nonblocking_process),

test/test_wifimanager/test_main.h

@@ -42,6 +42,7 @@ void test_config_portal_already_active();
 void test_get_config_portal_ssid();
 void test_root_render_menu_state_transitions();
 void test_root_render_snapshot_consistency();
+void test_root_render_interleaved_context_isolation();
 
 // Non-blocking tests
 void test_nonblocking_process();

test/test_wifimanager/tests/test_root_render_lifecycle.cpp

@@ -2,6 +2,59 @@
 #include <Arduino.h>
 #include <WiFiManager.h>
 #include <WiFiManagerHandlers.h>
+#include <TemplateEngine.h>
+#include "templates/RootSelector.h"
+
+namespace {
+
+const char kEmptyTemplateChunk[] PROGMEM = "";
+const char kTestTitle[] PROGMEM = "WiFiManager";
+const char kTestSubtitle[] PROGMEM = "Root Test";
+
+const char* dynamicStringGetter(void* userData) {
+    const auto* value = static_cast<const String*>(userData);
+    return value ? value->c_str() : "";
+}
+
+size_t dynamicStringLengthGetter(const char* data, void* /*userData*/) {
+    return data ? strlen(data) : 0;
+}
+
+void configureDescriptor(DynamicTemplateDescriptor& descriptor, String& value) {
+    descriptor.getter = &dynamicStringGetter;
+    descriptor.getLength = &dynamicStringLengthGetter;
+    descriptor.userData = &value;
+}
+
+void renderContextsInterleaved(TemplateContext& first, String& firstOutput,
+                               TemplateContext& second, String& secondOutput) {
+    uint8_t firstBuffer[31];
+    uint8_t secondBuffer[31];
+    bool firstDone = false;
+    bool secondDone = false;
+
+    while (!firstDone || !secondDone) {
+        if (!firstDone) {
+            size_t written = TemplateRenderer::renderNextChunk(first, firstBuffer, sizeof(firstBuffer));
+            if (written == 0) {
+                firstDone = true;
+            } else {
+                firstOutput.concat(reinterpret_cast<const char*>(firstBuffer), written);
+            }
+        }
+
+        if (!secondDone) {
+            size_t written = TemplateRenderer::renderNextChunk(second, secondBuffer, sizeof(secondBuffer));
+            if (written == 0) {
+                secondDone = true;
+            } else {
+                secondOutput.concat(reinterpret_cast<const char*>(secondBuffer), written);
+            }
+        }
+    }
+}
+
+} // namespace
 
 void test_root_render_menu_state_transitions() {
     Serial.println("[TEST]   Testing root menu state transitions...");
@@ -62,3 +115,68 @@ void test_root_render_snapshot_consistency() {
 
     Serial.println("[TEST]   Root render snapshot consistency test completed successfully");
 }
+
+void test_root_render_interleaved_context_isolation() {
+    Serial.println("[TEST]   Testing root render interleaved context isolation...");
+
+    PlaceholderRegistry registryA(8);
+    PlaceholderRegistry registryB(8);
+
+    registryA.registerProgmemData("%SCRIPTS%", kEmptyTemplateChunk);
+    registryA.registerProgmemData("%STYLES%", kEmptyTemplateChunk);
+    registryA.registerProgmemData("%PAGE_TITLE%", kTestTitle);
+    registryA.registerProgmemData("%SUBTITLE%", kTestSubtitle);
+
+    registryB.registerProgmemData("%SCRIPTS%", kEmptyTemplateChunk);
+    registryB.registerProgmemData("%STYLES%", kEmptyTemplateChunk);
+    registryB.registerProgmemData("%PAGE_TITLE%", kTestTitle);
+    registryB.registerProgmemData("%SUBTITLE%", kTestSubtitle);
+
+    String menuA = F("<div>Menu A</div>");
+    String statusA = F("<div>Status A</div>");
+    String menuB = F("<div>Menu B</div>");
+    String statusB = F("<div>Status B</div>");
+
+    DynamicTemplateDescriptor menuDescriptorA{};
+    DynamicTemplateDescriptor statusDescriptorA{};
+    DynamicTemplateDescriptor menuDescriptorB{};
+    DynamicTemplateDescriptor statusDescriptorB{};
+
+    configureDescriptor(menuDescriptorA, menuA);
+    configureDescriptor(statusDescriptorA, statusA);
+    configureDescriptor(menuDescriptorB, menuB);
+    configureDescriptor(statusDescriptorB, statusB);
+
+    TEST_ASSERT_TRUE_MESSAGE(registryA.registerDynamicTemplate("%MENU%", &menuDescriptorA),
+                             "Registry A menu placeholder should register");
+    TEST_ASSERT_TRUE_MESSAGE(registryA.registerDynamicTemplate("%STATUS%", &statusDescriptorA),
+                             "Registry A status placeholder should register");
+    TEST_ASSERT_TRUE_MESSAGE(registryB.registerDynamicTemplate("%MENU%", &menuDescriptorB),
+                             "Registry B menu placeholder should register");
+    TEST_ASSERT_TRUE_MESSAGE(registryB.registerDynamicTemplate("%STATUS%", &statusDescriptorB),
+                             "Registry B status placeholder should register");
+
+    TemplateContext contextA;
+    TemplateContext contextB;
+    contextA.setRegistry(&registryA);
+    contextB.setRegistry(&registryB);
+
+    TemplateRenderer::initializeContext(contextA, WM_ROOT_TEMPLATE);
+    TemplateRenderer::initializeContext(contextB, WM_ROOT_TEMPLATE);
+
+    String outputA;
+    String outputB;
+    renderContextsInterleaved(contextA, outputA, contextB, outputB);
+
+    TEST_ASSERT_NOT_EQUAL(-1, outputA.indexOf("Menu A"));
+    TEST_ASSERT_NOT_EQUAL(-1, outputA.indexOf("Status A"));
+    TEST_ASSERT_EQUAL(-1, outputA.indexOf("Menu B"));
+    TEST_ASSERT_EQUAL(-1, outputA.indexOf("Status B"));
+
+    TEST_ASSERT_NOT_EQUAL(-1, outputB.indexOf("Menu B"));
+    TEST_ASSERT_NOT_EQUAL(-1, outputB.indexOf("Status B"));
+    TEST_ASSERT_EQUAL(-1, outputB.indexOf("Menu A"));
+    TEST_ASSERT_EQUAL(-1, outputB.indexOf("Status A"));
+
+    Serial.println("[TEST]   Root render interleaved context isolation test completed successfully");
+}