Unify package and archive modes

[podtserkovskiy]

• Use the same code for package and archive modes (the package parsing implementation)
• Delete archive parsing implementation added in Support for archive mode #258
• Bump golang.org/x/tools to v0.26.0 to support archives v2 and unblock go1.25 support (already landed update golang.org/x/tools to v0.36.0 #276)

Closes #272

[podtserkovskiy]

cc @JamyDev

[JamyDev]

Seems sane to me. Tagging @sywhang for review.

[podtserkovskiy]

@sywhang @linzhp Could you please review this PR?
It also unblocks Go1.25 compatibility golang/go#74462

I have two commits to simplify review

• step1: re-uses "package" implementation for archive by removing receiver for methods
• step2: makes both "package" and "archive" to work with ExportFile + upgrades x/tools for modern compiler support

[podtserkovskiy]

Hey folks, is there a chance to get this PR merged?

[sywhang]

Thanks for this PR, and sorry for the delay in response. The Uber Go team is fairly occupied lately so we've got a bit of catch up reviews to do.

Just took a look at this PR and it looks good, but there are some behavioral changes in archive mode that's being "fixed" as a result of the code merging that might be worth adding to CHANGELOG:

• we now error out on type constraints in archive mode.
• we now handle type aliases explicitly in archive mode.

Feel free to modify CHANGELOG, otherwise I plan on merging this tomorrow morning and will be adding these ourselves later before releasing.

[podtserkovskiy]

No worries, thank you for the review. I've added information about this change to the CHANGELOG.

[sywhang]

thanks!