Add sdkconfig.defaults and tasks.py for project configuration and build automation

- Created sdkconfig.defaults to store default configuration settings for the project.
- Added tasks.py to define various build and management tasks using Invoke

tasks.py

@@ -0,0 +1,50 @@
+from invoke import task
+
+@task
+def cleanbuild(c):
+    """Clean build: fullclean and build the project"""
+    c.run("idf.py fullclean")
+    c.run("idf.py build")
+
+
+@task
+def build(c):
+    """Build the project"""
+    c.run("idf.py build")
+
+
+@task
+def flash(c):
+    """Flash the project to device"""
+    c.run("idf.py flash")
+
+
+@task
+def monitor(c, port="/dev/ttyUSB0"):
+    """Monitor serial output from device"""
+    c.run(f"idf.py monitor -p {port}")
+
+
+@task
+def run(c, port="/dev/ttyUSB0"):
+    """Build, flash, and monitor in sequence"""
+    build(c)
+    flash(c)
+    monitor(c, port)
+
+
+@task
+def clean(c):
+    """Clean build artifacts"""
+    c.run("idf.py fullclean")
+
+@task 
+def config(c):
+    """Open menuconfig to edit project settings"""
+    c.run("idf.py menuconfig --color-scheme=monochrome", pty=True)
+
+
+@task
+def saveconfig(c):
+    """Save current config as sdkconfig.defaults"""
+    c.run("idf.py save-defconfig")