Various Bug Fixes and Tailrec Cleanup

[CAG2Mark]

• Fixed two possible dormant bugs in the handler runtime where the continuation chain was not unlinked/relinked properly. (I only discovered these bugs when re-using the handler runtime for the shadow stack handler experimentation.) CC @AnsonYeung
• Made the tailrec pass idempotent by rewriting known calls to functions within each SCC into calls to the merged loop definition and added the corresponding tests.
• Cleaned up and refactored some logic in the tailrec pass to make it less error-prone.

[CAG2Mark]

Typo in the latest commit, it should be "make worker private". It seems making the worker private actually enables some optimizations.

[CAG2Mark]

It seems the wrappers for the mutually tail-recursive function definitions were never given the inline annotation, so I've added that now

[Copilot]

Pull request overview

Fixes handler continuation-chain bookkeeping and makes tail-recursion optimization idempotent.

Changes:

• Corrects handler frame unlinking and relinking.
• Rewrites recursive SCC calls to merged loop functions.
• Adds and updates tail-recursion golden tests.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
Block.scala	Adds flattened function parameter symbols.
TailRecOpt.scala	Refactors argument handling and SCC rewriting.
Runtime.mls	Fixes continuation-chain bookkeeping.
Runtime.mjs	Regenerates compiled runtime output.
TailRecOpt.mls	Adds idempotence coverage and snapshots.
MultiArgLists.mls	Adds curried/spread-call coverage and snapshots.

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[LPTK]

LGTM, thanks!