fix deallocate alignment in string_impl::destroy

[Ramya-9353]

Split out from #1179 as requested.

Repro: parse a truncated document like {"some key here": with test/checking_resource.hpp as the resource. The abandoned key fails alignment == it->second.second.

Cause: string_impl::destroy frees a key string with the default alignment (max_align), but both key_t constructors allocate it with alignof(char). The default resource ignores the argument, so this only bites upstreams that bucket by alignment.

Fix: pass alignof(char) to match the allocation. Both test cases fail before the fix and pass after.

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2026-08-05 16:49:29 UTC

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Build time: 2026-08-05 17:11:00 UTC

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