[FifteenPen]

Three fixes in reading Unreal Engine 4.27 shaders for the Switch 2, found on Persona 3 Reload (040091C0232EE000, project xrd777, IoStore, shader format SF_GLSL_SAGE). Its shaders are inline in the cooked packages in its IoStore containers, as in Mario & Luigi: Brothership.

• packing/uepak: pakchunk1, 2 and 4 hold only audio and fonts (.awb, .usm, .ufont). inline_shaders took any pak without inline shaders for one with shader code archives, so the NSP script's decode step searched those paks for archives, found none, and stopped. A pak that names no shader code archive, cooked package or global shader cache now holds neither kind (None, like an empty pak). When no pak has archives but some have inline shaders, the decode step says so and goes on to the split.
• packing/split: SF_GLSL_SAGE records are LSLG records, as on the Switch, but with an NVN2 control section (version 0xc9), whose code length is at +0x44 rather than +0x704. uepak.lslg reads both. Before this, every one of the game's 3,429 shader files was rejected.
• packing/split: the global shader cache holds ray tracing records (stage tags S1–S3, e.g. FDefaultMainCHS) that NVN has no stage for. The first one made the whole file unreadable, every global shader with it (the UI's among them, so the game's dialogs and menus didn't draw). They are now left out.

Tests in test_uepak_iostore.py cover each. The game's profile comes in a separate PR.