Add initial Compute binary support

[Kyle-Ye]

Summary

• Add Compute framework as an alternative backend via binary xcframework dependency
• Refactor Package.swift dependency resolution into three-way path: Compute / AttributeGraph / OAG
• Add AttributeGraphVendor enum and Compute-specific API shims in GraphShims
• Extract setupDPFDependency() to share DarwinPrivateFrameworks setup logic

Test plan

• OPENATTRIBUTEGRAPH_OPENATTRIBUTESHIMS_COMPUTE=1 swift build resolves and builds with Compute
• OPENATTRIBUTEGRAPH_OPENATTRIBUTESHIMS_COMPUTE=0 swift build falls back to AttributeGraph/OAG path
• Existing CI (compatibility tests) unaffected

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 32.08%. Comparing base (2a5d82a) to head (f190761).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@ Coverage Diff @@## main #197 +/- ##
=======================================
Coverage 32.08% 32.08% =======================================
Files 70 70 Lines 2596 2596 =======================================
Hits 833 833 Misses 1763 1763 

Flag	Coverage Δ
ios	32.10% <ø> (ø)
macos	9.95% <ø> (ø)
ubuntu	0.00% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
Sources/OpenAttributeGraphShims/Graph+Debug.swift	0.00% <ø> (ø)

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[augmentcode]

🤖 Augment PR Summary

Summary: This PR introduces initial support for using the Compute framework as an alternative backend for OpenAttributeGraph.

Changes:

• Refactors Package.swift dependency selection into a 3-way choice: Compute / Apple AttributeGraph (via DarwinPrivateFrameworks) / OpenAttributeGraph (OAG) fallback.
• Adds an optional Compute binary .xcframework dependency (URL/checksum/version controlled via environment variables).
• Introduces AttributeGraphVendor and exports vendor-specific shims/typealiases to unify APIs across backends.
• Extracts setupDPFDependency() to share DarwinPrivateFrameworks setup logic across compatibility tests and normal builds.
• Disables the Darwin-only debug dictionary/dot helpers when building against Compute due to API mismatch.

Technical Notes: Backend selection is driven by OPENATTRIBUTEGRAPH_OPENATTRIBUTESHIMS_COMPUTE / OPENATTRIBUTEGRAPH_OPENATTRIBUTESHIMS_ATTRIBUTEGRAPH, and Compute builds currently pin platforms to newer OS versions.

_{🤖 Was this summary useful? React with 👍 or 👎}

[augmentcode]

Review completed. 2 suggestions posted.

Comment augment review to trigger a new review at any time.