feat: V1 prototype — Vite/React/TS tileset generator

- Scaffold: package.json, tsconfig.json, vite.config.ts, index.html
- src/lib/imageProcessor.ts: full pipeline (normalize, offset, seam repair, export, validation)
- src/components/UploadPanel.tsx: drag-and-drop, file picker, clipboard paste
- src/components/SettingsPanel.tsx: all controls per spec
- src/components/PreviewPanel.tsx: Original / Tileable / Repeated tabs
- src/components/ErrorBanner.tsx: dismissible error/warning banners
- src/App.tsx: root component wiring everything together
- src/index.css: dark premium glassmorphism theme w/ Inter font

node_modules/source-map-js/lib/mapping-list.js

@@ -0,0 +1,79 @@
+/* -*- Mode: js; js-indent-level: 2; -*- */
+/*
+ * Copyright 2014 Mozilla Foundation and contributors
+ * Licensed under the New BSD license. See LICENSE or:
+ * http://opensource.org/licenses/BSD-3-Clause
+ */
+
+var util = require('./util');
+
+/**
+ * Determine whether mappingB is after mappingA with respect to generated
+ * position.
+ */
+function generatedPositionAfter(mappingA, mappingB) {
+  // Optimized for most common case
+  var lineA = mappingA.generatedLine;
+  var lineB = mappingB.generatedLine;
+  var columnA = mappingA.generatedColumn;
+  var columnB = mappingB.generatedColumn;
+  return lineB > lineA || lineB == lineA && columnB >= columnA ||
+         util.compareByGeneratedPositionsInflated(mappingA, mappingB) <= 0;
+}
+
+/**
+ * A data structure to provide a sorted view of accumulated mappings in a
+ * performance conscious manner. It trades a neglibable overhead in general
+ * case for a large speedup in case of mappings being added in order.
+ */
+function MappingList() {
+  this._array = [];
+  this._sorted = true;
+  // Serves as infimum
+  this._last = {generatedLine: -1, generatedColumn: 0};
+}
+
+/**
+ * Iterate through internal items. This method takes the same arguments that
+ * `Array.prototype.forEach` takes.
+ *
+ * NOTE: The order of the mappings is NOT guaranteed.
+ */
+MappingList.prototype.unsortedForEach =
+  function MappingList_forEach(aCallback, aThisArg) {
+    this._array.forEach(aCallback, aThisArg);
+  };
+
+/**
+ * Add the given source mapping.
+ *
+ * @param Object aMapping
+ */
+MappingList.prototype.add = function MappingList_add(aMapping) {
+  if (generatedPositionAfter(this._last, aMapping)) {
+    this._last = aMapping;
+    this._array.push(aMapping);
+  } else {
+    this._sorted = false;
+    this._array.push(aMapping);
+  }
+};
+
+/**
+ * Returns the flat, sorted array of mappings. The mappings are sorted by
+ * generated position.
+ *
+ * WARNING: This method returns internal data without copying, for
+ * performance. The return value must NOT be mutated, and should be treated as
+ * an immutable borrow. If you want to take ownership, you must make your own
+ * copy.
+ */
+MappingList.prototype.toArray = function MappingList_toArray() {
+  if (!this._sorted) {
+    this._array.sort(util.compareByGeneratedPositionsInflated);
+    this._sorted = true;
+  }
+  return this._array;
+};
+
+exports.MappingList = MappingList;