ath79/nand: profile glinet_gl-ar300m-nand silently overridden to glinet_gl-ar300m-nor during image build

### Description When requesting a build for `target: ath79/nand` with `profile: glinet_gl-ar300m-nand`, the ASU server silently substitutes the profile with `glinet_gl-ar300m-nor` in the resulting `build_cmd`, producing a NOR image instead of the requested NAND image. No error or warning is returned to indicate the profile was changed. ### Steps to Reproduce ```bash curl -X POST https://sysupgrade.openwrt.org/api/v1/build \ -H "Content-Type: application/json" \ -d '{ "target": "ath79/nand", "version": "25.12.0", "profile": "glinet_gl-ar300m-nand", "packages": ["luci"] }' ``` ### Expected Behavior The build should use `PROFILE=glinet_gl-ar300m-nand` and produce a NAND sysupgrade image. ### Actual Behavior The `build_cmd` in the response contains: ``` PROFILE=glinet_gl-ar300m-nor ``` The resulting image is built for NOR flash, not NAND. Flashing this image on a NAND device would be incorrect and potentially dangerous. ### Environment - ASU server: `sysupgrade.openwrt.org` - Target: `ath79/nand` - Version: `25.12.0` - Profile requested: `glinet_gl-ar300m-nand` - Profile used by server: `glinet_gl-ar300m-nor` - Device: GL.iNet GL-AR300M (NAND variant) ### Additional Context The GL-AR300M is a dual-flash device with both a NOR (16MB) and NAND (128MB) variant. The two profiles are distinct and not interchangeable. The NAND profile should be available under the `ath79/nand` target.