fix(import): share repeated KML styles before resource checks

docs/CURRENT-STATE.md

@@ -4331,9 +4331,9 @@ are omitted rather than framing the wrong part of the globe.
 - **An imported file cannot make the page fetch anything.** Before `KmlDataSource` reads a KML/KMZ document, `sanitizeKmlDocument` removes `NetworkLink`, `NetworkLinkControl`, `ScreenOverlay`, `PhotoOverlay`, `Model` and `Tour`, every `href` that is not an image packed in the same KMZ or a `data:image/` URL (an icon then falls back to Cesium's default pin, drawn locally, and a `GroundOverlay` left without an image is dropped), every `styleUrl` that is not a local `#id`, and placemark `description`/`BalloonStyle`/`Snippet` HTML and `ExtendedData` before metadata processing. GeoJSON `marker-symbol` (a maki icon asset) is dropped. KMZ images are served from blob URLs, one per packed image however many hrefs name it (`kmzImageResolver`). The hint says when something was left out. `scripts/qa-geo-import.mjs` imports files that name a trap host in each of those places and fails on any request that leaves the app's own origin.
 - **Imported metadata stays inert.** After loading, `scrubImportedEntities` removes every entity's description, native label, properties and KML extended data, and keeps the name only as plain text without control characters, at most 120 characters. GeoJSON is loaded with a `describe` that builds no HTML. The file name is shown with `textContent` only.
 - **KMZ** is read by a small zip reader (`readZipEntries`: stored and deflated entries through the platform `DecompressionStream`; no encryption, no ZIP64). The main document is `doc.kml`, else the shallowest `.kml`; relative hrefs resolve only to entries inside the archive.
-- **Bounds.** A file may be at most 50 MB (`MAX_IMPORT_BYTES`), a KMZ may inflate to at most 120 MB in total (`MAX_KMZ_INFLATED_BYTES`, the zip-bomb stop), one file may create at most 20,000 Cesium entities, including multipart geometries and KML parent containers (`MAX_IMPORT_ENTITIES`) and 250,000 vertices (`MAX_IMPORT_POSITIONS`), and a KML/KMZ at most 2,000 `<href>` and `<Style>` elements (`MAX_KML_LINKS`), counted before Cesium builds anything (`countGeoJsonGeometry`, `countKmlGeometry`, and while reading GPX), and the entity count is checked again after loading. At most 12 files are on the globe at once (`MAX_IMPORTED_FILES`): imports run one batch at a time, so two picks or drops in quick succession cannot pass the cap; files over it are not read. A refused file names its reason in the hint and does not stop the rest of the batch; a file with nothing to draw is refused.
+- **Bounds.** A file may be at most 50 MiB (`MAX_IMPORT_BYTES`), a KMZ may inflate to at most 120 MiB in total (`MAX_KMZ_INFLATED_BYTES`, the zip-bomb stop), one file may create at most 20,000 Cesium entities, including multipart geometries and KML parent containers (`MAX_IMPORT_ENTITIES`) and 250,000 vertices (`MAX_IMPORT_POSITIONS`), and a KML/KMZ at most 2,000 normalized style definitions (including named StyleMaps) and distinct surviving image links (`MAX_KML_LINKS`). Identical KML styles are shared after metadata and remote-reference cleanup, preserving inline overrides and local style references; repeated copies do not exhaust the style budget. Folder containers count toward the entity budget. Files of 20–30 MB fit within the byte limit; drawing complexity is bounded separately. Geometry is counted before Cesium builds anything (`countGeoJsonGeometry`, `countKmlGeometry`, and while reading GPX), and the entity count is checked again after loading. At most 12 files are on the globe at once (`MAX_IMPORTED_FILES`): imports run one batch at a time, so two picks or drops in quick succession cannot pass the cap; files over it are not read. A refused file names its reason in the hint and does not stop the rest of the batch; a file with nothing to draw is refused.
 - **Keyboard.** Hide, show and remove rebuild the list without losing focus: the same control on the same row keeps it, a removed row hands it to the next row (else the Import button).
-- Gate: `node scripts/qa-geo-import.mjs` (dev server up). Unit: `src/data/geoFileImport.test.mjs`, `src/ui/geoFileImport.test.mjs`, `src/ui/flyToDataSource.test.mjs`.
+- Gate: `node scripts/qa-geo-import.mjs` (dev server up). Large-file gate: `node scripts/qa-geo-import-large.mjs [--file /absolute/path/to/sample.kml]` tests a 27.6 MB repeated-style fixture, compares its graphics with an unshared Cesium control, and records matched frame times on the actual WebGL renderer. Unit: `src/data/geoFileImport.test.mjs`, `src/ui/geoFileImport.test.mjs`, `src/ui/flyToDataSource.test.mjs`.
 
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