feat(compiler): support unknown-typed class fields

[patlux]

Support class fields and parameter properties whose TypeScript type is unknown.

class Base {
  inherited: unknown;
}

class Holder extends Base {
  value: unknown;
  static current: unknown = "ready";

  constructor(public input: unknown) {
    super();
  }
}

• Store unknown fields through checked-dynamic storage.
• Initialize fresh and inherited instance slots to the immortal dynamic undefined value in both backends.
• Cover uninitialized, initialized, inherited, assigned, initialized-static, and parameter-property cases.
• Remove the obsolete diagnostic; initializer-less static fields remain outside the supported static-field surface.

Focused local Plain and sanitized C/LLVM tests, diagnostics, lint, workspace build, and git diff --check pass. The full GitHub Actions matrix is pending maintainer approval for this fork PR.

[vercel]

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