feat(language): establish hgraph IR boundary

[hhenson]

Summary

• add a dedicated hgl_graph_ir layer between typed HIR and the execution backends
• lower independently owned canonical types, compile-time type expressions, operator contracts, callable interfaces, effects, and typed capabilities
• preserve canonical operator identity separately from native registry spelling
• expose deterministic hgl check --dump-hgraph-ir output
• restage descriptor-dependent typed-HIR work under the native-interface stage and deferred-call completion under hgraph IR

This checkpoint is deliberately marked Interfaces, not Executable; backend migration follows body, state, lifecycle, activation, traversal, output, and provider-plan lowering.

Validation

• 29/29 HGL CTest tests
• 141 hgraph-IR assertions across 6 cases
• full native and Python 3.14 stack gates are running on this tip

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-09-05T14:50:00.132638Z	3a1038f	PR opened
🔒 Security Review	✅ Completed 2026-09-05T14:49:38.439952Z	3a1038f	PR opened

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[chatgpt-codex-connector]

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: 3a1038f33f

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• Comment "@codex review".

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud