Unify Heltec V4 OLED, TFT and headless display selection

Detect OLED or the original stock TFT touch assembly in ordinary V4.2/V4.3
images. Add saved live display.type auto/oled/tft/off selection and report
the active selection in board output. Keep sensors on primary I2C, preserve
shared power, and isolate TFT FSPI from radio HSPI through sleep and changes.

Consolidate future picker/build choices only with application capability
proof. Retain exact legacy OTA identities and separate R8 hardware images.
Document controls and physical qualification limits.

Validation: five serialized Full builds with capability/size/RAM checks;
focused host tests, existing R8/T-Deck/OLED regressions, build-profile suite,
and picker/provider tests. V4.3 OLED live changes and off/auto reboot
persistence passed on Mercerwood. Physical TFT qualification remains pending.

docs/_javascript/firmware_picker.js

@@ -822,8 +822,20 @@
       releaseBoundControl(profile, "combinedCompanion"));
   }
 
+  function unifiedV4DisplayProfile(profile) {
+    return Boolean(profile && profile.hardware === "heltec_v4" &&
+      profile.controls && profile.controls.platform === "ESP32_PLATFORM" &&
+      profile.controls.display === true && releaseBoundControl(profile, "unifiedV4Display"));
+  }
+
   function consolidationSuccessor(profile, candidate) {
     if (!profile || !candidate || profile.role !== candidate.role) return false;
+    if (/^heltec_v4(?:_3)?(?:_expansionkit)?(?:_tft)?$/.test(profile.hardware) &&
+        profile.hardware !== "heltec_v4" && unifiedV4DisplayProfile(candidate)) {
+      return candidate.feature === profile.feature && candidate.ota === profile.ota &&
+        (!profile.sensorProfile || profile.sensorProfile === candidate.sensorProfile) &&
+        (profile.role !== "companion" || isFullCompanion(candidate));
+    }
     if (/^PicoW_companion_radio_(usb|ble|wifi)$/.test(profile.target)) {
       return combinedPicoCompanion(candidate);
     }
@@ -1725,6 +1737,10 @@
       requested[field] = params.get(field) || "";
     });
     [
+      ...["heltec_v4_3", "heltec_v4_tft", "heltec_v4_3_tft", "heltec_v4_expansionkit",
+        "heltec_v4_expansionkit_tft", "heltec_v4_3_expansionkit_tft"].map(function (hardware) {
+        return [hardware, "heltec_v4", unifiedV4DisplayProfile];
+      }),
       ["heltec_rc32_without_display", "heltec_rc32", function (profile) { return optionalAutoDisplayProfile(profile); }],
       ["heltec_v4_expansionkit", "heltec_v4", function (profile) { return ["repeater", "room"].includes(profile.role) && releaseBoundControl(profile, "oledExpansionCompatible"); }],
       ["heltec_v4_r8_tft_portrait", "heltec_v4_r8_tft", function (profile) { return ["repeater", "room"].includes(profile.role) && releaseBoundControl(profile, "displayRotation"); }],
@@ -2011,6 +2027,10 @@
     if (combinedPicoCompanion(profile)) {
       notes.push("This Companion image includes USB, Bluetooth LE and WiFi together. Separate transport firmware is unnecessary; this image does not add a wireless firmware updater.");
     }
+    if (unifiedV4DisplayProfile(profile)) {
+      notes.push("One ordinary Heltec V4 image supports V4.2/V4.3 with OLED, the stock touch TFT kit, or no screen. The saved display.type setting selects auto, oled, tft or off; board reports the detected revision and active display. R8 uses its separate hardware image.");
+      notes.push("When changing from a legacy TFT or expansion-kit target, use a local USB installation or a supported WiFi application update. Their LoRa OTA target IDs remain distinct; never force a different target's LoRa OTA package.");
+    }
     if (releaseBoundControl(profile, "oledExpansionCompatible")) {
       notes.push("The same OLED firmware supports the base Heltec V4 and its OLED expansion kit. Existing expansion-kit OTA identities still require their exact historical update or a local USB migration.");
     }
@@ -2375,6 +2395,9 @@
     if (infrastructure && (info.updateMethods || []).includes("bluetooth")) section("Bluetooth firmware update", [
       { label: "Start DFU", commands: ["start ota"], text: "Use the exact board's application DFU ZIP with the matching Bluetooth-capable bootloader." },
     ]);
+    if (unifiedV4DisplayProfile(profile)) section("Display type", ["auto", "oled", "tft", "off"].map(function (type) {
+      return {label: type === "auto" ? "Automatic" : type === "off" ? "Screen off" : type.toUpperCase(), commands: ["set display.type " + type]};
+    }), "Saved choice applies immediately. Check with get display.type and board. Automatic mode continues without a screen if no supported display is detected.");
     if ((full || releaseBoundControl(profile, "displayRotation")) && info.display) section("Display rotation", [0, 90, 180, 270].map(function (angle) {
       return { label: angle === 0 ? "Board default" : angle + " degrees", commands: ["set display.rotation " + angle] };
     }), "Use on supported displays; 0 restores the board default. Check with get display.rotation.");