fix(dyn-input): re-sync fields immediately after point commits (#35)

`sync_dyn_fields` only ran during `ViewportMove`, so a typed-coord
or click-driven point commit left the previous iteration's field
shape in place until the user nudged the mouse. After the first
LINE click that meant the stale `[X, Y]` (built when there was no
base) kept serving the next point's input as cartesian even though
the command-default for a "Point with base" is now polar
`[Distance, Angle]`. The original #35 fix preserved a
`,`-reshaped cartesian set on purpose, but the same machinery now
also held onto a never-explicitly-chosen `[X, Y]` carried over from
"no base" → "has base".

Track that intent explicitly with `dyn_user_reshaped` (set in
`dyn_comma_advance`, cleared on point commit and command start)
and only treat a non-matching shape as acceptable while that flag
is on. Re-run `sync_dyn_fields` from every point-commit path
(command-line typed coord, mouse click, dynamic-input locked
commit) so the freshly updated `has_base` state immediately picks
the right default and the user sees polar fields without having
to move the mouse first.

src/app/commands.rs

@@ -15,6 +15,9 @@ impl OpenCADStudio {
         // Reset the last committed point so the first click of the new command
         // is not constrained by ortho/polar relative to a previous command's endpoint.
         self.last_point = None;
+        // A fresh command starts at the polar/cartesian default — clear
+        // any `,`-driven reshape from a previous command (#35).
+        self.dyn_user_reshaped = false;
 
         if let Some(path_str) = cmd.strip_prefix("OPEN_RECENT:") {
             let path = PathBuf::from(path_str);