perf: add --version fast-path to skip full import chain

When the user runs `codeflash --version`, read the version string
and exit immediately without importing cli, telemetry, models, or
any other heavy modules. This mirrors the pattern used in pip where
`pip --version` was optimized from 138ms to 20ms (7x).

Before: 524ms (imports cli.py -> cfapi -> models -> libcst -> ...)
After:  ~16ms (imports only codeflash.version)

Author: KRRT7

codeflash/main.py

@@ -22,6 +22,13 @@
 
 def main() -> None:
     """Entry point for the codeflash command-line interface."""
+    # Fast path: --version exits before importing the full stack
+    if len(sys.argv) == 2 and sys.argv[1] == "--version":
+        from codeflash.version import __version__
+
+        print(f"Codeflash version {__version__}")
+        return
+
     from pathlib import Path
 
     from codeflash.cli_cmds.cli import parse_args, process_pyproject_config