closes #652: class methods from precompiled .js drop on instance (v0.5.795)

[proggeramlug]

Summary

Closes #652 — class methods from precompiled .js files in node_modules drop on instance. typeof p.query was undefined, fields silently missing, blocking any precompiled npm-published package that exposes a class with instance methods (@perryts/mysql's Pool / Connection, several others).

Root cause: cjs_wrap.rs left every class X { ... } declaration INSIDE the synthetic IIFE that re-shapes module.exports. Perry's HIR saw the class as exported: false (it lived in a closure body, not at module scope), and the consumer's named import resolved to _cjs.X — a runtime property access, not the class declaration. new ClassRef(...) then allocated an empty *ObjectHeader with no constructor + no methods.

Fix: new extract_top_level_class_decls(source) helper does a brace-balanced scan (handles strings / template literals / line + block comments) of the CJS source and hoists top-level class X { ... } declarations OUT of the IIFE to the outer module scope. The IIFE body still has the original exports.X = X reference, but it now resolves via closure. Hoisted class names are emitted as export { X }; (direct re-export) so the consumer's named import resolves to the actual class. Detection is conservative — only class keyword at column-0 + optional indent — so nested classes inside functions / blocks stay inside the IIFE.

Test fixture

New test-files/issue_652/ exercises the full pattern:

• node_modules/minilib/index.js with class Base { greet() {} } + class Pool extends Base { async query() {} } + exports.{Base,Pool} = ...
• main.ts imports both, instantiates them, calls instance methods + super() + async methods

Out of scope

Classes whose body references module / exports / require directly (class X { static foo = require('./y') }) — uncommon for precompiled npm output; the current implementation hoists the class block before the IIFE runs, so any require() inside the class body wouldn't work. Filed as a separate followup if it surfaces.

Test plan

• Issue's original repro shape: new Pool({url}).query("SELECT 1") returns {rows:[{sql,ok:true}]}
• extends + super() works
• Multiple classes in one file all hoist
• 7 sanity tests pass byte-identical to Node