Make Linux runtime bundles resolve sibling libraries

[leehack]

Problem and fix

Published Linux LiteRT-LM runtime loading can fail with libwebgpu_dawn.so not found, including CPU requests that preload companions. The sampler carries Bazel build-tree RUNPATHs and Dawn has no SONAME, so loading absolute companion paths does not reliably resolve dependencies.

Stage the complete Linux prebuilt inventory, including dlopen-only accelerators, and normalize the packaged Dawn SONAME and all Linux RUNPATHs to sibling lookup via $ORIGIN. Perform this before model smoke hashes are recorded. Install patchelf in Linux build and qualification jobs. Source files and non-Linux packaging are unchanged.

Validation

• 181 tooling tests passed on macOS (one real Linux test skipped there).
• Real Linux loader regression passed in a disposable Linux container, without LD_LIBRARY_PATH/LD_PRELOAD; missing metadata reproduces failure, normalization restores loading, repeated normalization remains valid.
• Actual published v0.17.0-4 sampler reproduced missing Dawn before normalization and loaded successfully after normalization in Linux x64 container. This is loader evidence, not GPU inference.
• Added production staging/package-overlay regression for dlopen-only libraries following independent review feedback.
• Published unmodified v0.17.0-4 Qwen3/Gemma4 CPU/GPU inference passed on NVIDIA L4 with LD_LIBRARY_PATH; this fix still requires rebuilt artifact qualification without that workaround.
• All 17 final-head checks passed, including nine platform builds, candidate verification, and Linux/Windows/macOS Qwen inference. Independent blocking review accepted head cd70b1c6d75b380e910ff45e6bbc3b63695b97d7 against current main 8174e0e868d3c40999cab23a7078ca36eab6190d: no blocking findings, zero unresolved threads, zero known PR-caused P1 regressions. No release or downstream pin changes in this PR.

Related to #47 and leehack/llamadart#510. Do not close desktop GPU qualification until Windows and rebuilt-artifact validation complete.

The host ELF identity is preserved: broad SONAME rewriting reproduced a profiling shutdown crash, while the narrowed correction passed a same-input load/shutdown control. Read-only staged Bazel files are temporarily made owner-writable and their permissions restored in finally.