Add eSim-ORFS integration with PDK-aware netlist validator

[Divinesoumyadip]

Hey team,
I've been exploring the eSim-ORFS integration path and wanted to
start with a concrete foundation. This PR adds the initial skeleton
for automating the handoff from eSim's schematic export to OpenROAD
Flow Scripts.
The core idea is simple so before a .cir.out netlist reaches ORFS,
we validate it against the target PDK to catch unmappable primitives
early to avoiding silent failures during placement and routing.

Also its included

pdk_validator.py: skeleton for checking .cir.out against PDK cells., orfs_config_gen.py: will auto-generate ORFS config.mk from netlist. and init.py: module init.

This is the starting point. Happy to discuss the design direction
before building out the full implementation soon.

[Divinesoumyadip]

Hey @Shanthipriya20 , implemented the full working version based on your feedback. The parser now handles real .cir.outSPICE netlists, validates all components against the sky130 HD standard cell library, flags analog primitives like voltage sources as skipped, and blocks config generation if unmappable primitives are found. orfs_config_gen.py auto-generates a complete config.mk only after validation passes. Both scripts are tested and working. Would love your review!

[Divinesoumyadip]

Hey @Shanthipriya20 , tested the parser against all three cases you mentioned. Basic logic gates pass cleanly, hierarchical schematics now correctly identify internal user-defined subcircuits separately from PDK cells so they don't get flagged as unmappable, and parameterized components like R, C, M with W/L parameters are correctly skipped as analog primitives. All three test netlists pass. Test files are in src/orfs_integration/tests/. Ready for your review!