feat(settings): drawing_settings gains limits, grid/snap, ortho/polar, psltscale, annotation scale, unit formats and current styles

Headlessly, grid/snap are stored on the active VPORT, CANNOSCALE in
AcDbVariableDictionary (+ an ACAD_SCALELIST entry), and LIMMIN/LIMMAX on
the model-space layout as well as the header — measured: the header alone
is overwritten at save. Registry-saved variables (AUTOSNAP, POLARANG, …)
are refused with capability registry_sysvar instead of vanishing.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FKFStjEFzpGyLq5bMpWxTd

discovery/aliases.py

@@ -498,7 +498,20 @@ TOOL_ALIASES: dict[str, ToolAliases] = {
         ),
     ),
     "drawing_settings": ToolAliases(
-        acad=("UNITS", "DDUNITS", "OSNAP", "DSETTINGS", "LTSCALE", "DIMSCALE"),
+        acad=(
+            "UNITS",
+            "DDUNITS",
+            "OSNAP",
+            "DSETTINGS",
+            "LTSCALE",
+            "DIMSCALE",
+            "LIMITS",
+            "GRID",
+            "SNAP",
+            "ORTHO",
+            "PSLTSCALE",
+            "CANNOSCALE",
+        ),
         synonyms=(
             "drawing units",
             "millimetres or inches",
@@ -506,6 +519,16 @@ TOOL_ALIASES: dict[str, ToolAliases] = {
             "dimension scale",
             "linetype scale",
             "object snap settings",
+            "drawing limits",
+            "turn the grid on",
+            "grid spacing",
+            "snap spacing",
+            "ortho mode",
+            "polar tracking",
+            "annotation scale",
+            "architectural units",
+            "current dimension style",
+            "current text style",
         ),
     ),
     "drawing_undo": ToolAliases(