Implement SCPI parser

Adds SCPIParser class with parse() method that handles:
- IEEE 488.2 common commands (*IDN?, *RST, etc.)
- Query commands (ending with '?')
- Commands with comma-separated arguments
- Whitespace stripping

src/py_dvt_ate/instruments/scpi.py

@@ -30,3 +30,57 @@ class SCPICommand:
         For regular commands like "VOLT", returns "VOLT".
         """
         return self.header.rstrip("?")
+
+
+class SCPIParser:
+    """Parse SCPI command strings.
+
+    Handles both IEEE 488.2 common commands (e.g., *IDN?, *RST) and
+    instrument-specific commands (e.g., VOLT 3.3, TEMP:SETPOINT?).
+
+    Examples:
+        >>> parser = SCPIParser()
+        >>> cmd = parser.parse("*IDN?")
+        >>> cmd.header, cmd.is_query
+        ('*IDN?', True)
+        >>> cmd = parser.parse("VOLT 3.3")
+        >>> cmd.header, cmd.arguments
+        ('VOLT', ['3.3'])
+    """
+
+    def parse(self, command_string: str) -> SCPICommand:
+        """Parse a SCPI command string.
+
+        Args:
+            command_string: The raw SCPI command string to parse.
+
+        Returns:
+            SCPICommand with parsed header, arguments, and query flag.
+
+        Examples:
+            "*IDN?" -> SCPICommand("*IDN?", [], True)
+            "VOLT 3.3" -> SCPICommand("VOLT", ["3.3"], False)
+            "TEMP:SETPOINT?" -> SCPICommand("TEMP:SETPOINT?", [], True)
+            "CONF:VOLT:DC 10,0.001" -> SCPICommand("CONF:VOLT:DC", ["10", "0.001"], False)
+        """
+        command_string = command_string.strip()
+        if not command_string:
+            return SCPICommand(header="", arguments=[], is_query=False)
+
+        is_query = command_string.endswith("?")
+
+        # Split into header and arguments on first whitespace
+        parts = command_string.split(None, 1)
+        header = parts[0]
+        arguments: list[str] = []
+
+        if len(parts) > 1:
+            # Parse comma-separated arguments
+            arg_string = parts[1]
+            arguments = [arg.strip() for arg in arg_string.split(",")]
+
+        return SCPICommand(
+            header=header,
+            arguments=arguments,
+            is_query=is_query,
+        )