CommonJS model: Rule 1 misses nested writes to exported values, eval payloads, arguments and require.cache #33

Found in the PR #29 round-14 review. Rule 1 (the allowlist over uses of module/exports) misses some ways of reaching the exports object. Each repro keeps the file modelled and loses a pre-PR edge:

• Nested writes to an exported value (module.exports = o) by any form other than o.x =: Object.assign(o, {b}) or Object.defineProperty(o, 'b', …) inside a called function; a local alias (const p = o; function init(){ p.b = b }); destructuring ([o.b] = [b]).
• Literal eval payloads are visited but never scanned: eval('(function(){ exports.b=b })()'), eval('Object.assign(exports,{b})'), eval('this.b=b').
• Other paths to the object: arguments[0].b = b / arguments[2].exports = … at top level; require.cache[module.id].exports.b = b; require('module')._cache[__filename].exports.run = run; a computed method key class K { [(this.b=b,'q')](){} }. The key evaluates with the module's this, but the scan treats it as bound.

Fix direction: run the Rule 1 scan on expanded eval payloads; give exported values the same write rules as aliases (builtin writers, aliases, patterns); bail on arguments, require.cache/Module._cache and this in computed keys.