refactor(compat-eslint): generic-typed defineShape + whenAbsent tests

Addresses review on PR #89:

  defineShape<TsT extends ts.Node>(...): each call site now binds the
  TS node type via generic. tsField is constrained to keys of TsT, so
  typos like `tsField: 'thenSttement'` fail at compile time. consts
  callback parameter is auto-inferred (no per-shape `(tn: ts.X) =>`
  annotation needed).

  46 defineShape sites updated with their concrete TS type parameter.
  All build + tests still pass.

  Two focused factory unit tests in lazy-estree.test:
    - TSTypeQuery.typeArguments returns undefined (not null) for absent
      slot, AND is an own-property (eager parity), AND memoises on
      second read.
    - ReturnStatement.argument returns null (not undefined) for bare
      `return;` — the default whenAbsent='null' is honoured.

Also confirmed via Dify bench that there's no perf regression — cold
~11s (improved vs PR #88's 13s baseline; the earlier 14s reading was
disk warmup), warm ~6s. The factory's hidden-class shape transitions
land on V8's monomorphic happy path.

Author: johnsoncodehk