add recovery firmware with OTA updater and recovery web interface

Co-authored-by: Cursor <cursoragent@cursor.com>

scripts/upload_factory.py

@@ -0,0 +1,28 @@
+# Makes `pio run -t upload` write the app into the factory partition instead of ota_0.
+#
+# Set `custom_app_offset` to the factory partition offset. The otadata image (boot_app0.bin) that
+# PlatformIO normally writes selects ota_0, so it's swapped for a blank one, which makes the
+# bootloader start the factory app.
+from pathlib import Path
+
+Import("env")
+
+OTADATA_SIZE = 0x2000
+
+offset = env.GetProjectOption("custom_app_offset", "")
+if offset:
+    # ESP32_APP_OFFSET itself is recalculated from the partition table later in the build
+    env.Replace(UPLOADCMD=env.get("UPLOADCMD", "").replace("$ESP32_APP_OFFSET", offset))
+
+    blank_otadata = Path(env.subst("$BUILD_DIR")) / "otadata_blank.bin"
+    blank_otadata.parent.mkdir(parents=True, exist_ok=True)
+    blank_otadata.write_bytes(b"\xff" * OTADATA_SIZE)
+
+    def swap(path):
+        return str(blank_otadata) if Path(env.subst(str(path))).name == "boot_app0.bin" else path
+
+    # the platform has already expanded FLASH_EXTRA_IMAGES into UPLOADERFLAGS, so patch both
+    env.Replace(FLASH_EXTRA_IMAGES=[(o, swap(p)) for o, p in env.get("FLASH_EXTRA_IMAGES", [])])
+    env.Replace(UPLOADERFLAGS=[swap(flag) for flag in env.get("UPLOADERFLAGS", [])])
+
+    print(f"Upload: app at {offset}, otadata blanked")