feat(wind): add ECMWF IFS as a second wind model

Add ECMWF IFS 10 m wind alongside NOAA GFS, selectable at runtime.

The /api/wind proxy becomes a model dispatcher: `?model=gfs|ifs` (default gfs,
unknown → 400), cached per model+cycle+grid. IFS reads the keyless ECMWF Open
Data JSON Lines `.index` (note: `<stem>.index`, not `<grib2>.index`), byte-range
fetches only the `10u`/`10v` messages, decodes them with the same ecCodes WASM
path, and resamples with the existing grid code (ECMWF grids start at lo1=180;
the resampler already wraps columns).

The client layer gains a `model` parameter (setParams/getParams) with a
generation guard so a model switch aborts and refetches exactly once. Registered
as an enabled+options layer with a `model` enum.

Validated end-to-end against the real 2026-09-14 06z IFS cycle on Node 25
(180x91 grid at 2°, 131,040-byte payload, plausible mean |u|/|v|), and GFS
still passes the same check.

Attribution: contains modified Copernicus/ECMWF IFS forecast data, licensed
under CC BY 4.0. Verified: npm test (3412 pass, 0 fail), check:boundaries.

docs/CURRENT-STATE.md

@@ -3402,3 +3402,5 @@ releases imagery layers/listeners on replacement. Destroy invalidates pending
 work and releases owned resources, including late factory results. Supplied 3D
 tilesets remain owned by the caller; tilesets created through the controller's
 factory are added to its viewer and removed on destruction.
+
+Wind supports GFS/IFS models.