Add app metadata introspection APIs

[TheHypnoo]

Summary

• Add getAppVersion(), getAppBuildNumber(), and getBundleId() to perry/system.
• Read app metadata from perry.toml during compilation and bake it into the LLVM backend as compile-time metadata.
• Wire the new APIs through dispatch, API manifest, object cache invalidation, and TypeScript declarations.
• Add regression coverage for default metadata fallback and perry.toml parsing.

Why

Apps already define project.version, project.build_number, and bundle identifiers in perry.toml, but there was no runtime-facing API to read those values from TypeScript. This made apps duplicate metadata in hand-maintained constants, which can drift between releases.

This implements the feature requested in #673 by exposing the values through perry/system while keeping perry.toml as the source of truth.

Validation

• cargo test -p perry app_metadata_tests --quiet
• cargo check -p perry-codegen --quiet
• cargo test -p perry-dispatch --quiet
• rustfmt --check on touched Rust files
• Manual end-to-end compile/run for the fallback path
• Manual end-to-end compile/run with a temporary perry.toml, confirming 9.8.7, 123, and the target-specific bundle id are returned

Closes #673