feat(shader): publish and load prebuilt resource plans - #62

Publish existing resource plans alongside compiled variants when packing a populated renderer cache, then load those plans before the writable cache. Packed and loose plan entries require matching source, format and request keys and valid checksums. Missing or invalid entries fall back to normal compilation. Raw archive extraction does not synthesize runtime resource plans.

Seven linear topic/dependency commits on main 8856f180ca0b5605574842666ffbc8b0bb69cc4d; head 5fb29c2dca3e3f27e8f2b3eed7eb53bcf97d6345. Main's shader cache format 36 and the archive tool's 48-byte encoded-entry header are retained. The loader from boykopovar#5792 is already merged. No obsolete loader switches are restored.

This fork draft includes the earlier four archive-tool/dependency commits from SaloQT's boykopovar#6032, preserving authorship, followed by the resource-plan implementation, portable link correction and regression. boykopovar#6032 is now closed in favor of the split recompiler PR boykopovar#6296. This branch has not yet incorporated that revised split or the later tool trimming; dependency alignment remains pending before upstream submission. It is a development integration, not a duplicate upstream archive-tool submission.

Validation on this head: Linux x86-64 GCC Release, renderer SPIRV-Tools enabled. Full runtime libs, agc_shader_archive, shader_archive_tests, agc_shader_disk_cache_tests and shader_cache_file_read_tests built successfully. shader_cache_file_read, agc_shader_disk_cache and shader_archive passed with zero skips (2.28 s), with APS5_VERIFY_SRT_COMPACT=1. Conventions and whitespace pass.

The production cross-process regression removes writable plan entries before packed-plan and loose-plan loads. All 16 fixtures must produce their expected output without frontend builds; writable plans are restored for corrupt-pack fallback. The archive regression covers mixed entry types, mapping lifetime, plan serialization and rejected invalid/foreign entries. An earlier disabled-prebuilt-lookup control failed with 16 frontend builds / 16 plan misses; that control was not repeated for this base refresh.

The local build differs from the public head only by a private SPIRV-Tools teardown repair in the submodule. That dependency change is excluded from this PR; the official pin is not independently validated by these results. No current Windows, complete-suite, native title or FPS result is claimed. Earlier CI/runtime measurements apply only to their recorded revisions and are not validation of this head. No game assets, packs, raw logs or binaries are committed.

• Depends on: feat(recompiler): add an uncached compile entry point and entry key helpers for offline tools boykopovar/AnyPS5#6296 (upstream boykopovar/AnyPS5; revised split pending); earlier feat(tools): add an offline shader archive tool that publishes prebuilt packs boykopovar/AnyPS5#6032 tool/dependency commits are included
• Unblocks: none
• GPUs tested: n/a (CPU cache/serialization/archive tests)
• AI-assisted: yes