feat: unify CAD workflows on DesignIR 3.0

cad-agent-studio/README.md

@@ -34,10 +34,20 @@ Open `http://127.0.0.1:53821`.
 
 Uploads and generated tasks are stored under `data/tasks/<taskId>`.
 
-The model authors DesignIR 2.0, CAD Router selects text-to-cad or SimpleCADAPI,
-and the DesignIR pipeline performs a teacher-free isolated STEP rebuild.
-Uploaded STEP is teacher and acceptance truth; it is never imported by the
-reconstruction compiler.
+For new text/image models, the model authors semantic DesignIR 3.0 and CAD
+Router selects text-to-cad or SimpleCADAPI. The generated STEP is materialized
+as a non-authoritative SurfaceIR snapshot while the semantic layer remains the
+edit source. For uploaded STEP, chat calls the deterministic
+`reconstruct_uploaded_step` tool, which executes CAD Router's DesignIR 3.0 /
+SurfaceIR adapter, independently rebuilds STEP, runs geometry acceptance, and
+publishes only perturbation-validated editable parameters. Uploaded STEP is
+teacher and acceptance truth; it is never imported by the reconstruction
+compiler.
+
+Follow-up chat edits on a reconstructed task use
+`edit_designir3_parameter`. The tool accepts only a parameter and value already
+covered by the published validation range, reruns teacher-side semantic edit
+acceptance, and publishes a new DesignIR 3.0 plus STEP revision.
 
 CAD Agent Studio does not start the standalone CAD Viewer service. Generated
 models keep DesignIR as the editable contract and STEP as the geometry artifact.