refactor: remove XML export, JSON-only for .rfflow files

- Remove XML builder, format query param, and XML tests
- Simplify ExportFlowModal (no format picker)
- Simplify rfflowParser (JSON-only)
- Remove format field from schemas and types

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/app/api/endpoints/tree_transfer.py

@@ -1,8 +1,6 @@
 """Flow export/import endpoints (.rfflow files)."""
-import json
 import logging
 import re
-import xml.etree.ElementTree as ET
 from datetime import datetime, timezone
 from typing import Annotated, Optional
 from uuid import UUID
@@ -43,45 +41,6 @@ def _slugify(name: str) -> str:
     return re.sub(r'[-\s]+', '-', slug)
 
 
-def _build_xml(envelope: FlowExportEnvelope) -> str:
-    """Build XML representation of an .rfflow export."""
-    root = ET.Element("rfflow")
-    root.set("version", envelope.rfflow_version)
-
-    ET.SubElement(root, "exported_at").text = envelope.exported_at.isoformat()
-    ET.SubElement(root, "source_app").text = envelope.source_app
-    ET.SubElement(root, "format").text = "xml"
-
-    flow_el = ET.SubElement(root, "flow")
-    flow = envelope.flow
-
-    ET.SubElement(flow_el, "name").text = flow.name
-    ET.SubElement(flow_el, "description").text = flow.description or ""
-    ET.SubElement(flow_el, "tree_type").text = flow.tree_type
-    ET.SubElement(flow_el, "version").text = str(flow.version)
-    ET.SubElement(flow_el, "author_name").text = flow.author_name or ""
-
-    if flow.category:
-        cat_el = ET.SubElement(flow_el, "category")
-        ET.SubElement(cat_el, "name").text = flow.category.name
-        ET.SubElement(cat_el, "slug").text = flow.category.slug
-
-    tags_el = ET.SubElement(flow_el, "tags")
-    for tag in flow.tags:
-        ET.SubElement(tags_el, "tag").text = tag
-
-    # Store tree_structure as JSON string in CDATA-safe text
-    ts_el = ET.SubElement(flow_el, "tree_structure")
-    ts_el.text = json.dumps(flow.tree_structure)
-
-    if flow.intake_form:
-        if_el = ET.SubElement(flow_el, "intake_form")
-        if_el.text = json.dumps(flow.intake_form)
-
-    ET.indent(root)
-    return ET.tostring(root, encoding="unicode", xml_declaration=True)
-
-
 # --- Export ---
 
 @router.get("/{tree_id}/export")
@@ -89,9 +48,8 @@ async def export_tree(
     tree_id: UUID,
     db: Annotated[AsyncSession, Depends(get_db)],
     current_user: Annotated[User, Depends(get_current_active_user)],
-    format: str = Query("json", pattern="^(json|xml)$"),
 ):
-    """Export a tree as a downloadable .rfflow file (JSON or XML)."""
+    """Export a tree as a downloadable .rfflow JSON file."""
     # Load tree with relationships + author name
     result = await db.execute(
         select(Tree)
@@ -139,25 +97,15 @@ async def export_tree(
         rfflow_version="1.0",
         exported_at=datetime.now(timezone.utc),
         source_app="ResolutionFlow",
-        format=format,
         flow=flow_data,
     )
 
     slug = _slugify(tree.name)
 
     # Audit log
-    await log_audit(db, current_user.id, "tree.export", "tree", tree.id, {"format": format})
+    await log_audit(db, current_user.id, "tree.export", "tree", tree.id)
     await db.commit()
 
-    if format == "xml":
-        content = _build_xml(envelope)
-        return Response(
-            content=content,
-            media_type="application/xml",
-            headers={"Content-Disposition": f'attachment; filename="{slug}.rfflow"'},
-        )
-
-    # JSON
     content = envelope.model_dump_json(indent=2)
     return Response(
         content=content,

backend/app/schemas/tree_export.py

@@ -1,6 +1,6 @@
 """Schemas for .rfflow file export and import."""
 from datetime import datetime
-from typing import Optional, Any, Literal
+from typing import Optional, Any
 from pydantic import BaseModel, Field
 
 from app.schemas.tree import TreeType
@@ -30,7 +30,6 @@ class FlowExportEnvelope(BaseModel):
     rfflow_version: str = "1.0"
     exported_at: datetime
     source_app: str = "ResolutionFlow"
-    format: Literal["json", "xml"] = "json"
     flow: FlowExportData
 
 
@@ -39,7 +38,6 @@ class FlowImportRequest(BaseModel):
     rfflow_version: str = Field(..., description="Must be '1.0'")
     exported_at: datetime
     source_app: str = "ResolutionFlow"
-    format: Literal["json", "xml"] = "json"
     flow: FlowExportData