Add validator chain config overrides

internal/core/config/file_config_test.go

@@ -300,6 +300,61 @@ pipelines:
 	}
 }
 
+func TestParseFileConfigStageLocalValidatorOverrides(t *testing.T) {
+	cfg := parseAndApplyConfig(t, `
+version: 2
+pipelines:
+  example:
+    input: fake/input
+    chunk:
+      module: generic
+      validators: []
+    artifacts:
+      events:
+        extract:
+          module: fake/extract
+          validators:
+            - fake/validator
+            - module: fake/llm-validator
+              llm_profile: careful
+              options:
+                threshold: 0.7
+        merge:
+          module: appendorder
+          validators: []
+        normalize:
+          module: noop
+`)
+
+	profile := cfg.Pipelines["example"]
+	if !profile.Chunk.Validators.Set || len(profile.Chunk.Validators.Validators) != 0 {
+		t.Fatalf("chunk validator override = %#v, want explicit empty", profile.Chunk.Validators)
+	}
+	lane := profile.Artifacts["events"]
+	if !lane.Extract.Validators.Set {
+		t.Fatalf("extract validator override Set = false, want true")
+	}
+	validators := lane.Extract.Validators.Validators
+	if len(validators) != 2 {
+		t.Fatalf("extract validators = %#v, want two validators", validators)
+	}
+	if validators[0].Module != "fake/validator" {
+		t.Fatalf("first validator = %#v, want fake/validator", validators[0])
+	}
+	if validators[1].Module != "fake/llm-validator" || validators[1].LLMProfile != "careful" {
+		t.Fatalf("second validator = %#v, want LLM validator with profile", validators[1])
+	}
+	if validators[1].Options["threshold"] != 0.7 {
+		t.Fatalf("second validator options = %#v, want threshold", validators[1].Options)
+	}
+	if !lane.Merge.Validators.Set || len(lane.Merge.Validators.Validators) != 0 {
+		t.Fatalf("merge validator override = %#v, want explicit empty", lane.Merge.Validators)
+	}
+	if lane.Normalize.Validators.Set {
+		t.Fatalf("normalize validator override Set = true, want omitted")
+	}
+}
+
 func TestApplyFileConfigRejectsDuplicateTrimmedPipelineIDs(t *testing.T) {
 	fileCfg, err := ParseFileConfigYAML([]byte(`
 version: 2