fix: preserve String trim alias identity

[ShiroKSH]

Summary

• make trimLeft share the exact function object used by trimStart
• make trimRight share the exact function object used by trimEnd
• add regression coverage for alias identity and canonical function names

Root cause

alloc_methods allocated a new native function for every property entry. Reusing the same native dispatch variant therefore did not preserve function-object identity, and the aliases exposed trimLeft and trimRight as their function names.

The canonical trim functions are now allocated once. Each alias installs the same function reference in a restamped property descriptor, preserving independent property ordering metadata.

Validation

• gleam check
• gleam test: 1561 passed, 0 failed
• filtered test262 trim suite: 8 execution passes, 0 execution failures
• gleam format --check for the changed files
• git diff --check

[vercel]

@ShiroKSH is attempting to deploy a commit to the alistair Team on Vercel.

A member of the Team first needs to authorize it.

[ShiroKSH]

@alii - Vercel is blocked on team authorization for this fork. Could you authorize the deployment or let me know if the PR can be reviewed without a preview? I can make any requested changes. Thanks!

[ShiroKSH]

Hi maintainers, this PR has been open for over two weeks. When you have a moment, I would appreciate a review. Thank you.

[alii]

Hello! Thank you for the contribution. Arc is currently a very early research project. It's not clear to me yet the direction that Arc should even head in at the moment. For this reason I am hesitant to accept contributions while I figure out the design of Arc.

What is the motivation for this change? Are you using Arc in production anywhere? It would be helpful to know how you are using Arc!

Thank you!