Initial MCP serial server implementation

FastMCP server for serial port access via Model Context Protocol:
- 10 tools: list, open, close, read, write, configure, flush, status
- 4 dynamic resources: ports list, data, status, raw hex
- USB device filtering (hides phantom ttyS ports by default)
- Full pyserial support with configurable baudrate/parity/etc

.env.example

@@ -0,0 +1,13 @@
+# MCP Serial Server Configuration
+
+# Default baud rate for serial connections
+MCSERIAL_DEFAULT_BAUDRATE=9600
+
+# Default timeout in seconds for read operations
+MCSERIAL_DEFAULT_TIMEOUT=1.0
+
+# Maximum number of concurrent serial port connections
+MCSERIAL_MAX_CONNECTIONS=10
+
+# Log level (DEBUG, INFO, WARNING, ERROR)
+MCSERIAL_LOG_LEVEL=INFO