feat(builtins): implement JsWeakSet safe wrapper

[KaustubhOG]

Implements JsWeakSet as a safe Rust wrapper around the ECMAScript WeakSet builtin, as part of #2098.

Changes

• core/engine/src/object/builtins/jsweakset.rs — new JsWeakSet wrapper with all methods
• core/engine/src/object/builtins/mod.rs — registered and re-exported JsWeakSet
• examples/src/bin/jsweakset.rs — usage example

Methods implemented

• new — creates an empty WeakSet
• add — adds an object to the set
• has — checks if an object exists
• delete — removes an object
• from_object — converts JsObject to JsWeakSet

Follows the same pattern as JsWeakMap (#4738) and JsSet.

Closes part of #2098

[github-actions]

Test262 conformance changes

Test result	main count	PR count	difference
Total	52,862	52,862	0
Passed	49,504	49,505	+1
Ignored	2,262	2,261	-1
Failed	1,096	1,096	0
Panics	0	0	0
Conformance	93.65%	93.65%	+0.00%

Fixed tests (1):

test/staging/sm/expressions/optional-chain-first-expression.js (previously Ignored)

[jedel1043]

LGTM!

[KaustubhOG]

LGTM!

hey i made some changes in #4724 as you suggested to me is it loooks fine

[codecov]

Codecov Report

❌ Patch coverage is 0% with 28 lines in your changes missing coverage. Please review.
✅ Project coverage is 57.18%. Comparing base (6ddc2b4) to head (2c419a4).
⚠️ Report is 701 commits behind head on main.

Files with missing lines	Patch %	Lines
core/engine/src/object/builtins/jsweakset.rs	0.00%	28 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4739      +/-   ##
==========================================
+ Coverage   47.24%   57.18%   +9.93%     
==========================================
  Files         476      552      +76     
  Lines       46892    60494   +13602     
==========================================
+ Hits        22154    34591   +12437     
- Misses      24738    25903    +1165     

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[jedel1043]

Looks fine, just needs a cargo fmt run

[KaustubhOG]

Looks fine, just needs a cargo fmt run

Yup ,while solving the conflicts in Jsweakmap and and weakset ,Ithe web one we uses I think it didn't do the cargo fmt , let me do Manually

[KaustubhOG]

@jedel1043 did the jsgeneratorfunction and the Asyncgenerator isn't checked on original pr #2098 is it currently outof scope(if they are in scope or not yet solved I think it can be fixed with the same process if i am not mistaken ,if that's the case I loved to raise pr for it), also thanks for quick guidence in this pr. I learned alot