Add automatic single-core ESP32 support (ESP32-C3, ESP32-S2) (#196)

* Initial plan

* Add ESP32-C3 single-core support with automatic core detection

- Modified signalDecoder.cpp to check CONFIG_FREERTOS_UNICORE
- Single-core ESP32 variants (ESP32-C3, ESP32-S2) run decoder on core 0 with priority 3
- Multi-core ESP32 variants run decoder on core 1 with priority 2
- Added documentation in README.md explaining the automatic detection

Co-authored-by: NorthernMan54 <19808920+NorthernMan54@users.noreply.github.com>

* Final verification complete - ESP32-C3 support ready

Co-authored-by: NorthernMan54 <19808920+NorthernMan54@users.noreply.github.com>

* Remove temporary codeql symlink

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: NorthernMan54 <19808920+NorthernMan54@users.noreply.github.com>

Author: Copilot

README.md

@@ -332,6 +332,19 @@ Wiring for ESP32 DOIT DevKit V1 and AI-Thinker R01 - SX1278
 
 ![image](https://github.com/diepeterpan/rtl_433_ESP/blob/master/docs/Ai-Thinker-Ra-01-Schematic-Diagram.png)
 
+## ESP32 Platform Support
+
+### Single-Core ESP32 Variants (ESP32-C3, ESP32-S2)
+
+The library automatically detects and supports single-core ESP32 variants such as the ESP32-C3 and ESP32-S2. The decoder task's CPU core assignment and priority are automatically adjusted based on the `CONFIG_FREERTOS_UNICORE` configuration:
+
+* **Single-core processors** (ESP32-C3, ESP32-S2): Decoder task runs on core 0 with priority 3
+* **Multi-core processors** (ESP32, ESP32-S3): Decoder task runs on core 1 with priority 2
+
+This configuration ensures compatibility with single-core ESP32 variants that only have core 0 available, preventing boot crashes that would occur if the task were pinned to the non-existent core 1.
+
+The `CONFIG_FREERTOS_UNICORE` flag is automatically set by the ESP-IDF/Arduino framework when compiling for single-core ESP32 variants, so no manual configuration is required.
+
 ## Wiring and Building the Example
 
 Details are [here](example/OOK_Receiver/README.md)

src/signalDecoder.cpp

@@ -41,8 +41,13 @@
 #  endif
 #endif
 
-#define rtl_433_Decoder_Priority 2
-#define rtl_433_Decoder_Core     1
+#ifdef CONFIG_FREERTOS_UNICORE
+#  define rtl_433_Decoder_Core     0
+#  define rtl_433_Decoder_Priority 3
+#else
+#  define rtl_433_Decoder_Core     1
+#  define rtl_433_Decoder_Priority 2
+#endif
 
 /*----------------------------- rtl_433_ESP Internals -----------------------------*/