fix(wasm): #1034 missing Date imports + #1035 __classDispatch arg padding

[proggeramlug]

Summary

• wasm runtime: rt.date_get_day missing → LinkError on any Date.prototype.getDay() reachable build #1034 — Date.prototype.getDay() on --target web LinkErrored at instantiation because rt.date_get_day was declared in the WASM import struct but never defined in the JS import object. Audit found ~30 additional Date methods (emit_memcall for date_get_utc_*, date_to_*, date_set_utc_*, date_get_timezone_offset, date_value_of, date_parse, date_utc, …) routed through the unified mem_call bridge but missing from __memDispatch — these wouldn't LinkError (only mem_call is named) but would silently return undefined. Added all of them.
• wasm runtime: __classDispatch doesn't pad missing args → BigInt(undefined) throw for any TS optional parameter #1035 — TS class methods with optional params threw TypeError: Cannot convert undefined to a BigInt whenever the caller omitted a param: the WASM ABI takes one i64 per declared slot, and args.map(__jsValueToBits) produces too few BigInts, so JS auto-coerces trailing undefined via BigInt(undefined) at the call site and throws. Added a __padBigintArgs(fn, prefix, bigintArgs) helper and applied it at all eight class- and closure-dispatch sites (the three __classDispatch/class_call_method paths plus closure_call_{0,1,2,3,spread} in both dispatch tables).
• wasm runtime: post-parse hang — object_get_dynamic repeats indefinitely with identical args after keyword tokenizer enters its outer loop #1037 — could not reproduce the keyword-tokenizer hang in isolation; minimal for (let ki = 0; ki < kws.length; ki++) over the same offset array runs cleanly on --target web. Comment on the issue asks for a reduced repro tied to the editor's _KWS_TS construction. The minimal test did surface a separate latent INT32_TAG decode gap in toJsValue (not the same bug as wasm runtime: post-parse hang — object_get_dynamic repeats indefinitely with identical args after keyword tokenizer enters its outer loop #1037) — not filed here.

Test plan

• cargo build --release -p perry-runtime -p perry-stdlib -p perry -p perry-ui-macos — clean.
• Repro wasm runtime: rt.date_get_day missing → LinkError on any Date.prototype.getDay() reachable build #1034 (const d = new Date(...); console.log(d.getDay())) compiles + instantiates on --target web — no more LinkError.
• Repro wasm runtime: __classDispatch doesn't pad missing args → BigInt(undefined) throw for any TS optional parameter #1035 (class T { parse(b: string, r?: number[]) { ... } }; new T().parse('hello')) returns the expected value — before fix this threw Cannot convert undefined to a BigInt.
• Minimal wasm runtime: post-parse hang — object_get_dynamic repeats indefinitely with identical args after keyword tokenizer enters its outer loop #1037-style for-loop runs to completion (does not hang).
• User to validate against the @honeide/editor repro once the build lands.