"No include path available" when including features

Noto Sans Bengali fails:

```
$ fontc NotoSansBengali.glyphspackage
[2025-10-06T08:27:15.236659Z ThreadId(1) fontc ERROR] FEA parsing failed with 1 errors, set log level to warn or higher (--log warn) for additional detail
```

I think reporting what went wrong with feature compilation is a reasonable default, but OK:

```
$ fontc NotoSansBengali.glyphspackage --log warn
[2025-10-06T08:28:04.574445Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'openTypeOS2VendorID'
[2025-10-06T08:28:04.574498Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'Enforce Compatibility Check'
[2025-10-06T08:28:04.574503Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'DisableAllAutomaticBehaviour'
[2025-10-06T08:28:04.574505Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'Write lastChange'
[2025-10-06T08:28:04.574507Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'Axis Mappings'
[2025-10-06T08:28:04.574509Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'Variable Font Origin'
[2025-10-06T08:28:04.574595Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'xHeight'
[2025-10-06T08:28:04.574600Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'xHeight'
[2025-10-06T08:28:04.574604Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'xHeight'
[2025-10-06T08:28:04.574607Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'xHeight'
[2025-10-06T08:28:04.574610Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'xHeight'
[2025-10-06T08:28:04.574613Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'xHeight'
[2025-10-06T08:28:04.574615Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'xHeight'
[2025-10-06T08:28:04.574619Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'xHeight'
[2025-10-06T08:28:04.574625Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'xHeight'
[2025-10-06T08:28:04.574628Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'xHeight'
[2025-10-06T08:28:04.574631Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'xHeight'
[2025-10-06T08:28:04.574635Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'xHeight'
[2025-10-06T08:28:04.574638Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'xHeight'
[2025-10-06T08:28:04.574642Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'xHeight'
[2025-10-06T08:28:04.574647Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'xHeight'
[2025-10-06T08:28:04.574652Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'xHeight'
[2025-10-06T08:28:04.574655Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'xHeight'
[2025-10-06T08:28:04.574658Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'xHeight'
[2025-10-06T08:28:04.574660Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'xHeight'
[2025-10-06T08:28:04.574663Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'xHeight'
[2025-10-06T08:28:04.574668Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'xHeight'
[2025-10-06T08:28:04.574671Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'xHeight'
[2025-10-06T08:28:04.574692Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'xHeight'
[2025-10-06T08:28:04.574696Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'xHeight'
[2025-10-06T08:28:04.574699Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'xHeight'
[2025-10-06T08:28:04.574702Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'xHeight'
[2025-10-06T08:28:04.574704Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'xHeight'
[2025-10-06T08:28:04.574710Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'xHeight'
[2025-10-06T08:28:04.574715Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'xHeight'
[2025-10-06T08:28:04.574718Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'xHeight'
[2025-10-06T08:28:04.574721Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'xHeight'
[2025-10-06T08:28:04.574735Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'xHeight'
[2025-10-06T08:28:04.574739Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'xHeight'
[2025-10-06T08:28:04.574741Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'Reencode Glyphs'
[2025-10-06T08:28:04.574744Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'xHeight'
[2025-10-06T08:28:04.574746Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'Reencode Glyphs'
[2025-10-06T08:28:04.574751Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'xHeight'
[2025-10-06T08:28:04.574753Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'Reencode Glyphs'
[2025-10-06T08:28:04.574757Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'xHeight'
[2025-10-06T08:28:04.574759Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'Reencode Glyphs'
[2025-10-06T08:28:04.574775Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'xHeight'
[2025-10-06T08:28:04.574777Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'Reencode Glyphs'
[2025-10-06T08:28:04.574780Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'xHeight'
[2025-10-06T08:28:04.574782Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'Reencode Glyphs'
[2025-10-06T08:28:04.574785Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'xHeight'
[2025-10-06T08:28:04.574788Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'Reencode Glyphs'
[2025-10-06T08:28:04.574790Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'xHeight'
[2025-10-06T08:28:04.574793Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'Reencode Glyphs'
[2025-10-06T08:28:04.574796Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'xHeight'
[2025-10-06T08:28:04.574812Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'Reencode Glyphs'
[2025-10-06T08:28:04.574816Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'xHeight'
[2025-10-06T08:28:04.574818Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'Reencode Glyphs'
[2025-10-06T08:28:04.574823Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'xHeight'
[2025-10-06T08:28:04.574825Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'Reencode Glyphs'
[2025-10-06T08:28:04.574828Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'xHeight'
[2025-10-06T08:28:04.574830Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'Reencode Glyphs'
[2025-10-06T08:28:04.584793Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'Master Icon Glyph Name'
[2025-10-06T08:28:04.584823Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'Master Icon Glyph Name'
[2025-10-06T08:28:04.584826Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'Replace Feature'
[2025-10-06T08:28:04.584833Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'Master Icon Glyph Name'
[2025-10-06T08:28:04.584835Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'Replace Feature'
[2025-10-06T08:28:04.584843Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'Master Icon Glyph Name'
[2025-10-06T08:28:04.584846Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'Replace Feature'
[2025-10-06T08:28:04.584851Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'Master Icon Glyph Name'
[2025-10-06T08:28:04.584854Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'Replace Feature'
[2025-10-06T08:28:04.584871Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'Master Icon Glyph Name'
[2025-10-06T08:28:04.584873Z ThreadId(1) glyphs_reader::font WARN] unknown custom parameter 'Replace Feature'
[2025-10-06T08:28:04.603111Z ThreadId(17) glyphs2fontir::source WARN] Invalid kern side: k_la-beng, no such glyph
[2025-10-06T08:28:04.604153Z ThreadId(15) fontbe::features WARN] Debug fea not written for 'compile failed' because --emit-debug is off
[2025-10-06T08:28:04.619199Z ThreadId(1) fontc ERROR] FEA parsing failed with 1 errors
[2025-10-06T08:28:04.619215Z ThreadId(1) fontc WARN] error: Failed to load source at 'features/NotoSansBengali.fea': 'No include path available'
in at 3:8
|
3 | include(features/NotoSansBengali.fea);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
```

And yet:

```
$ ls -l features/NotoSansBengali.fea
-rw-r--r-- 1 simon staff 81032 Oct 6 09:24 features/NotoSansBengali.fea
```

Start by running `fontc NotoSansBengali.glyphspackage` and compare it with the `--log warn` output. Trace the feature-compilation entry point and include-path handling for `features/NotoSansBengali.fea`, which the report shows exists locally. Done means the existing include is handled correctly and the reported failure is no longer caused by an unavailable include path.

Written by the indexing model from the issue text.