docs: document legacy and Plant 3D 2026 viewport mapping APIs

Plant3D2026/P_Rec_Annot/docs/dcf-control-comparison.md

@@ -1,3 +1,26 @@
-# DCF control comparison
+# CONTROL versus DryRun DCF comparison
 
-`DBMOD` covers only the active DWG. DCF and project metadata require paired control and DryRun fixture copies created from one fully closed state. This comparison has not yet been executed, so plugin-only DCF and metadata deltas remain unverified. Apply remains blocked.
+DBMOD covers only the active drawing. This procedure separately compares
+content-bearing project files after identical CONTROL and DryRun sessions.
+
+1. With Plant 3D closed and the Launcher session `RolledBack`, copy the local
+   fixture to `<FROZEN_FIXTURE>`.
+2. Create `<CONTROL_FIXTURE>` and `<DRYRUN_FIXTURE>` from that same frozen
+   state; calculate complete local SHA-256 inventories before each run.
+3. Open model and Ortho drawings in CONTROL through the same Launcher DryRun
+   launch contract, but invoke no P_Rec_Annot command. Close without saving,
+   wait for Launcher rollback, then calculate the after inventory.
+4. Repeat with DRYRUN and invoke each supported command twice. Close without
+   saving, wait for rollback, then calculate the after inventory.
+5. Compare deltas by logical relative path. Classify each content-bearing file
+   as `UNCHANGED`, `AUTODESK_BASELINE_CHANGE`, `PLUGIN_ONLY_CHANGE`, or
+   `INCONCLUSIVE`.
+
+Content-bearing groups include model DWG, Ortho DWG, `Piping.dcf`, remaining
+DCF/database files, `Project.xml` or equivalent project metadata, and Ortho
+metadata. Lock, cache, session, log, preview, and temporary files are reported
+separately and cannot establish project invariance.
+
+Any `PLUGIN_ONLY_CHANGE` blocks Apply. Full paths and hashes remain local;
+repository evidence contains only logical fixture markers, groups, counts, and
+classifications.