Add lifecycle, errata, internal-features, and layout_rules checks.

Cache distributor EOL/NRND/RoHS without inventing replacements, flag catalogued errata pull-ups only, and store layout_rules with a closed kind enum so millimetres stay null unless the datasheet stated a number.

Co-authored-by: Cursor <cursoragent@cursor.com>

tests/test_layout_rules.py

@@ -0,0 +1,54 @@
+"""layout_rules from datasheet — closed kind enum, no invented millimetres.
+
+Favor: decoupling_proximity with a numeric max_distance_mm and source_page;
+empty list is valid (explicit skip).
+Against: unknown kind is rejected; a non-numeric distance becomes null
+(not a guessed JEDEC 3 mm); thermal_via without min_via_count is kept
+but distance stays unset.
+"""
+
+from __future__ import annotations
+
+from backend.pinscopex.layout_rules import validate_layout_rules
+
+
+def test_valid_decoupling_proximity_keeps_distance():
+    ok, errors = validate_layout_rules([
+        {
+            "kind": "decoupling_proximity",
+            "pin": "VDD",
+            "cap_value_hint": "100nF",
+            "max_distance_mm": 2.0,
+            "same_layer": True,
+            "source_page": 14,
+        }
+    ])
+    assert errors == []
+    assert len(ok) == 1
+    assert ok[0]["max_distance_mm"] == 2.0
+    assert ok[0]["kind"] == "decoupling_proximity"
+
+
+def test_empty_list_is_explicit_skip():
+    ok, errors = validate_layout_rules([])
+    assert ok == []
+    assert errors == []
+
+
+def test_unknown_kind_rejected_and_bad_distance_not_invented():
+    ok, errors = validate_layout_rules([
+        {"kind": "jedec_land_pattern", "max_distance_mm": 3.0},
+        {
+            "kind": "decoupling_proximity",
+            "pin": "VDD",
+            "max_distance_mm": "close",
+            "source_page": 2,
+        },
+        {"kind": "thermal_via", "pin": "EP", "min_via_count": 4},
+    ])
+    assert any("kind" in e.lower() or "jedec" in e.lower() for e in errors)
+    dist_rows = [r for r in ok if r["kind"] == "decoupling_proximity"]
+    assert len(dist_rows) == 1
+    assert dist_rows[0]["max_distance_mm"] is None
+    via = [r for r in ok if r["kind"] == "thermal_via"]
+    assert len(via) == 1 and via[0]["min_via_count"] == 4