ci: adopt tiered contributor validation

ci/pr-test-policy.json

@@ -0,0 +1,32 @@
+{
+  "schema_version": 1,
+  "changed_line_coverage_floor": 50.0,
+  "always_tests": [
+    "tests/test_module_imports.py",
+    "tests/test_cli_boundaries.py",
+    "tests/test_runtime_contracts.py",
+    "tests/test_abliterate.py",
+    "tests/test_strategies.py"
+  ],
+  "infrastructure_paths": [
+    ".aiwg/**",
+    ".github/workflows/**",
+    "ci/**",
+    "scripts/check_*.py",
+    "scripts/select_pr_tests.py",
+    "pyproject.toml",
+    "uv.lock"
+  ],
+  "infrastructure_tests": [
+    "tests/test_aiwg_workspace_contracts.py",
+    "tests/test_ci_policy.py",
+    "tests/test_pr_test_selection.py",
+    "tests/test_quality_policy.py",
+    "tests/test_quality_gate_scripts.py",
+    "tests/test_supply_chain_policy.py",
+    "tests/test_test_policy.py"
+  ],
+  "excluded_test_prefixes": [
+    "tests/conditional/"
+  ]
+}

ci/test-quality-policy.json

@@ -3,7 +3,7 @@
   "minimums": {
     "repository_statement": 75.0,
     "repository_branch": 60.0,
-    "changed_line": 95.0,
+    "changed_line": 50.0,
     "mature_cpu_statement": 94.0,
     "mature_cpu_branch": 84.0,
     "mutation_score": 85.0,