feat(core,view): input cards with change tracking (plan B1 · C2)

- Three values per pier: defaults (as imported), input (generated), draft
  (current cards). Overrides = draft vs defaults; pending = draft vs input.
- Editable now: 코핑 폭, 코핑 길이, 말뚝 길이. Changing a card does not touch the
  3D view until 다시 생성; the header and the card show 변경 n.
- Revert puts a field back to its imported default.
- Project files store defaults and draft (optional; v1 files still open).
- Tests: 코핑 폭 3100 → 3300 gives one override and one pending change;
  regenerating clears pending but keeps the override; revert; file round trip.
- Not verified in a browser (no debuggable Chrome in this session).

Co-Authored-By: Claude Haiku 5.5 <noreply@anthropic.com>

src/style.css

@@ -587,3 +587,11 @@ table {
     height: 60vh;
   }
 }
+
+/* Input cards (2단계 C2): changed values are outlined in orange, with the imported default beside them. */
+.edit-card { margin-top: 12px; border-top: 1px solid #d5dde6; padding-top: 10px; }
+.edit-row { display: flex; align-items: center; gap: 8px; margin: 6px 0; flex-wrap: wrap; }
+.edit-row label { min-width: 150px; }
+.edit-row input { width: 110px; padding: 4px 6px; border: 1px solid #b9c4d0; border-radius: 4px; }
+.edit-row.changed input { border: 2px solid #e8833a; background: #fff6ee; }
+.edit-row.changed label { color: #a4530e; }