fix(runtime): inherit Object prototype on class instances

[proggeramlug]

Lands #8780.

A registered ES class instance whose class methods and accessors all missed was excluded from the ordinary Object.prototype read fallback, so inherited reads — String(new C()) among them — failed. Declared class instances do end their implicit prototype chain at Object.prototype, and their own methods are consulted before this fallback runs, so a miss must remain eligible.

The exclusion now additionally requires the class id to be unregistered, which keeps native and synthetic class ids on their existing intrinsic prototype paths:

if class_id != 0
    && !is_anon_shape_class_id(class_id)
    && !class_registry::is_class_id_registered(class_id)

Validation (on the merged result)

• All 30 lint-job checkers pass
• perry-runtime --lib (RUST_TEST_THREADS=1): 2674 passed, 0 failed
• perry-codegen --lib: 1230 passed, 0 failed
• perry-codegen --tests (all integration suites): 0 failures
• Squashed tree verified identical to the validated tree

The PR carried its own changelog.d/ fragment. No version bump.

Summary by CodeRabbit

• Bug Fixes
  • Fixed inherited Object.prototype properties on class instances.
  • Restored expected default toString and valueOf behavior, including normal string conversion for class instances.

[coderabbitai]

Caution

Review failed

The pull request is closed.

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: 9ad5f796-dd36-48cb-a4fb-822d2c2753e0

📥 Commits

Reviewing files that changed from the base of the PR and between 8e1367b and e7b24f9.

📒 Files selected for processing (2)

• changelog.d/8780-class-instance-object-prototype-read.md
• crates/perry-runtime/src/object/field_get_set/accessors.rs

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📝 Walkthrough

Walkthrough

Registered ES class instances now resolve inherited Object.prototype properties such as toString and valueOf. Unregistered native and synthetic class IDs remain excluded. A changelog entry documents the fix.

Changes

Class instance prototype lookup

Layer / File(s)	Summary
Prototype fallback eligibility crates/perry-runtime/src/object/field_get_set/accessors.rs, changelog.d/8780-class-instance-object-prototype-read.md	Registered class instances can use Object.prototype property fallback. Unregistered native and synthetic class IDs remain excluded. The changelog documents the corrected toString and valueOf behavior.

Estimated code review effort: 2 (Simple) | ~10 minutes

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch merge/b44

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