Finish MVP and dockerize

dlib/cv/ats_guard.py

@@ -0,0 +1,44 @@
+from __future__ import annotations
+
+from typing import Iterable
+
+from .schema import PatchPayload, PatchOperation, StructuredDocument
+
+
+class PatchValidationError(ValueError):
+    pass
+
+
+def validate_patchset(
+    document: StructuredDocument,
+    patches: Iterable[PatchPayload],
+    *,
+    max_changes: int = 12,
+    max_growth_ratio: float = 1.45,
+) -> None:
+    patch_list = list(patches)
+    if len(patch_list) > max_changes:
+        raise PatchValidationError(
+            f"Patchset exceeds max changes ({len(patch_list)} > {max_changes})"
+        )
+    block_map = {block.path: block for block in document.blocks}
+    for patch in patch_list:
+        block = block_map.get(patch.target_path)
+        if not block:
+            raise PatchValidationError(
+                f"Target path {patch.target_path} does not exist in base document"
+            )
+        if patch.operation == PatchOperation.REPLACE_TEXT:
+            if not patch.new_value:
+                raise PatchValidationError("replace_text requires new_value")
+            baseline = len(block.text.strip()) or 1
+            if len(patch.new_value.strip()) / baseline > max_growth_ratio:
+                raise PatchValidationError("Patch grows text beyond ATS safe threshold")
+        if (
+            patch.operation
+            in {PatchOperation.REMOVE_BLOCK, PatchOperation.SUPPRESS_BLOCK}
+            and block.block_type == "heading"
+        ):
+            raise PatchValidationError(
+                "Headings cannot be removed without manual confirmation"
+            )