feat: implemented multi page reflow

gateway/app/routers/edits.py

@@ -228,8 +228,6 @@ class ReflowRun(BaseModel):
     internalFontId: str
     fontSize: float
     color: str = "#000000"
-    # Original per-character advance (PDF units) of UNCHANGED source text, for pixel-perfect
-    # reflow spacing. Omitted for edited/new runs (engine re-measures those).
     advances: list[float] | None = None
 
 
@@ -243,9 +241,8 @@ class ReflowParagraphData(BaseModel):
     oldLineCount: int = 1
     align: Literal["left", "justify", "center", "right"] = "left"
     pushColumnLeft: float | None = None
+    paraId: str | None = None
     lines: list[list[ReflowRun]] | None = None
-    # Original per-line baseline + left anchor (parallel to `lines`), so unchanged lines reproduce
-    # the source's exact vertical spacing and left edge instead of a uniform fallback.
     lineBaselineY: list[float] | None = None
     lineX: list[float] | None = None
 
@@ -308,9 +305,6 @@ class EditsRequest(BaseModel):
     version: Literal["1.0"]
     operations: list[EditOperation]
 
-
-# Which PDF permission each edit operation requires. Unencrypted / owner-unlocked
-# docs report every flag True (in the engine), so this never blocks them.
 _OP_PERMISSION = {
     "highlight": "canAnnotate", "underline": "canAnnotate", "strikeout": "canAnnotate",
     "squiggly": "canAnnotate", "comment": "canAnnotate", "freehand": "canAnnotate",
@@ -357,10 +351,8 @@ def apply_edits_impl(document_id: str, request: EditsRequest):
                     import os
                     import tempfile
 
-                    # pyrefly: ignore [missing-import]
                     from PIL import Image   
 
-                    # Remove data URI header if present
                     if "," in img_data_str:
                         img_data_str = img_data_str.split(",", 1)[1]
 
@@ -368,13 +360,11 @@ def apply_edits_impl(document_id: str, request: EditsRequest):
                     img = Image.open(io.BytesIO(raw_bytes))
                     img_rgba = img.convert("RGBA")
 
-                    # Convert RGBA to BGRA
                     r, g, b, a = img_rgba.split()
                     img_bgra = Image.merge("RGBA", (b, g, r, a))
 
                     bgra_bytes = img_bgra.tobytes()
 
-                    # Create a temporary binary file to hold raw pixel data
                     fd, temp_path = tempfile.mkstemp(suffix=".bin", prefix="pdf_pixel_")
                     created_temp_files.append(temp_path)
                     try:
@@ -388,7 +378,6 @@ def apply_edits_impl(document_id: str, request: EditsRequest):
                     op["data"]["pixelWidth"] = img.width
                     op["data"]["pixelHeight"] = img.height
 
-                    # Delete base64 strings to keep JSON payload tiny
                     if "imageData" in op["data"]:
                         del op["data"]["imageData"]
 
@@ -396,16 +385,12 @@ def apply_edits_impl(document_id: str, request: EditsRequest):
         doc_copy = pdfengine.PdfDocument.load_from_memory(doc_info["bytes_data"])
         doc_copy.apply_edits(edits_json)
 
-        # Redaction and in-place text rewrites mutate existing objects, which do
-        # not round-trip cleanly through an incremental save — force a full save.
         full_save_types = {"redaction", "replace_text", "reflow_paragraph"}
         needs_full = any(op.get("type") in full_save_types for op in req_dict.get("operations", []))
         new_bytes = doc_copy.save_full() if needs_full else doc_copy.save_incremental()
 
         new_doc = pdfengine.PdfDocument.load_from_memory(new_bytes)
 
-        # Carry the original permissions forward — the saved bytes are decrypted, so
-        # a fresh load would report full access and defeat enforcement.
         new_info = document_store.add_document(
             filename=doc_info["filename"], bytes_data=new_bytes, doc_instance=new_doc,
             permissions=doc_info.get("permissions"),