feat: create examples and corresponding build config

platformio.ini

@@ -10,6 +10,7 @@
 
 [platformio]
 default_envs = esp01_1m
+src_dir = .
 
 [common]
 monitor_speed = 115200
@@ -28,6 +29,10 @@ board_build.partitions = partitions_ota_1M.csv
 board_build.flash_mode = dout          ; ESP‑01S uses DOUT on 1 Mbit flash
 board_build.flash_size = 1M
 lib_deps = ${common.lib_deps}
+build_src_filter = 
+    +<examples/base/*.cpp>
+    +<src/*.c>
+    +<src/*.cpp>
 
 [env:d1_mini]
 platform = platformio/espressif8266@^4.2.1
@@ -37,4 +42,23 @@ upload_speed = 115200
 monitor_speed = 115200
 board_build.flash_mode = dio           ; D1 Mini uses DIO on 4 Mbit flash
 board_build.flash_size = 4M
-lib_deps = ${common.lib_deps}
+lib_deps = ${common.lib_deps}
+build_src_filter = 
+    +<examples/base/*.cpp>
+    +<src/*.c>
+    +<src/*.cpp>
+
+[env:esp01_1m_relay]
+platform = platformio/espressif8266@^4.2.1
+board = esp01_1m
+framework = arduino
+upload_speed = 115200
+monitor_speed = 115200
+board_build.partitions = partitions_ota_1M.csv
+board_build.flash_mode = dout
+board_build.flash_size = 1M
+lib_deps = ${common.lib_deps}
+build_src_filter = 
+    +<examples/relay/*.cpp>
+    +<src/*.c>
+    +<src/*.cpp>