HS: chain .x after f(); translate window.X arrow setups — +5 functionCalls

Parser (lib/hyperscript/parser.sx):
- parse-poss case for "(" (function call) was building (call ...) and
  returning without recursing, so `f().x` lost the `.x` suffix and the
  compiler emitted (let ((it (f))) (hs-query-first ".x")). Now it tail-
  calls parse-poss on the constructed call so chains like f().x.y(),
  obj.method().prop, etc. parse correctly.

Generator (tests/playwright/generate-sx-tests.py):
- New js_expr_to_sx: translates arrow functions ((args) => body), object
  literals, simple property access / method calls / arith. Falls back
  through js_val_to_sx for primitives.
- New extract_window_setups: scans `evaluate(() => { window.X = Y })`
  blocks (with balanced-brace inner-body extraction) and returns
  (name, sx_value) pairs.
- Pattern 1 / Pattern 2 in generate_eval_only_test merge those window
  setups into the locals passed to eval-hs-locals, so HS expressions
  can reference globals defined by the test prelude.
- Object literal value parsing now goes through js_expr_to_sx first,
  so `{x: x, y: y}` yields `{:x x :y y}` (was `{:x "x" :y "y"}`).

Net: hs-upstream-expressions/functionCalls 0/12 → 5/12 (+5).
Smoke-checked put/set/scoping/possessiveExpression — no regressions.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

shared/static/wasm/sx/hs-parser.sx

@@ -331,7 +331,7 @@
             ((= (tp-type) "paren-open")
               (let
                 ((args (parse-call-args)))
-                (cons (quote call) (cons obj args))))
+                (parse-poss (cons (quote call) (cons obj args)))))
             ((= (tp-type) "bracket-open")
               (do
                 (adv!)