feat: enhance core-STA integration and timing analysis

- Updated soc_topology.json to include new fabric links for core, DMA, native, and APB interfaces.
- Refactored retrosoc.sv to utilize generated fabric links and included necessary SVH files for better modularity.
- Improved check_clock_reset_domains.py to validate hierarchical pins and added support for positive number checks.
- Modified regress.py to include OpenSTA in the regression commands.
- Enhanced README.md in the STA directory to clarify the timing analysis flow and supported PDK profiles.
- Removed outdated gen2.sdc file and replaced it with a dynamic SDC generation approach.
- Updated opensta.mk to generate SDC files dynamically based on the current domain map and pin map.
- Created generate_sdc.py to automate SDC generation from clock/reset domain inventory.
- Added tests for generated core-STA constraints to ensure coverage of current clock domains and validate pin map integrity.
- Introduced new timing metrics and warnings for the sky130 PDK in the quality checks.

tests/test_clock_reset_domains.py

@@ -30,6 +30,14 @@ def write_invalid_map(tmp_path: Path, document: dict[str, object]) -> Path:
 def test_clock_reset_domain_inventory_matches_the_rcu() -> None:
     result = check(DOMAIN_MAP)
     assert result.returncode == 0, result.stderr
+    document = json.loads(DOMAIN_MAP.read_text(encoding="utf-8"))
+    assert document["schema_version"] == 2
+    assert {domain["name"] for domain in document["domains"]} == {
+        "external",
+        "system",
+        "audio",
+        "dvp",
+    }
 
 
 def test_clock_reset_domain_inventory_rejects_unknown_domain_and_instance(tmp_path: Path) -> None:
@@ -44,3 +52,9 @@ def test_clock_reset_domain_inventory_rejects_unknown_domain_and_instance(tmp_pa
     result = check(write_invalid_map(tmp_path, document))
     assert result.returncode != 0
     assert "does not declare rst_sync instance" in result.stderr
+
+    document = json.loads(DOMAIN_MAP.read_text(encoding="utf-8"))
+    document["domains"][1]["sta"]["source_domain"] = "unknown"
+    result = check(write_invalid_map(tmp_path, document))
+    assert result.returncode != 0
+    assert "STA source references unknown domain" in result.stderr