feat: add --offline mode

[JoshuaKGoldberg]

PR Checklist

• Addresses an existing open issue: fixes 🚀 Feature: Add an explicit opt-in --offline mode #878
• That issue was marked as status: accepting prs
• Steps in CONTRIBUTING.md were taken

Overview

Adds --offline flag that skips running scripts. That includes a timeout for npm whoami, as I've found that command to hang when I'm on an airplane.

Also corrects a bit of the logic around adding the user as a contributor, while I'm in the area. And fixes up unit tests around that.

[codecov]

Codecov Report

Merging #879 (96cea60) into main (a51c624) will increase coverage by 2.71%.
The diff coverage is 94.00%.

@@            Coverage Diff             @@
##             main     #879      +/-   ##
==========================================
+ Coverage   90.83%   93.54%   +2.71%     
==========================================
  Files          89       89              
  Lines        4681     4711      +30     
  Branches      357      373      +16     
==========================================
+ Hits         4252     4407     +155     
+ Misses        428      303     -125     
  Partials        1        1              

Flag	Coverage Δ
create	71.97% <22.44%> (-0.33%)	⬇️
initialize	37.05% <61.22%> (?)
migrate	70.75% <18.36%> (-0.34%)	⬇️
unit	66.26% <86.00%> (+0.23%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
src/initialize/initializeWithOptions.ts	87.09% <100.00%> (+66.46%)	⬆️
src/shared/getGitHubUserAsAllContributor.ts	100.00% <100.00%> (ø)
src/shared/options/args.ts	100.00% <100.00%> (ø)
src/shared/options/optionsSchema.ts	100.00% <100.00%> (ø)
src/shared/options/readOptions.ts	92.76% <100.00%> (+0.06%)	⬆️
src/steps/addOwnerAsAllContributor.ts	100.00% <100.00%> (ø)
src/steps/addToolAllContributors.ts	100.00% <100.00%> (ø)
src/steps/finalizeDependencies.ts	100.00% <100.00%> (ø)
src/create/createWithOptions.ts	69.11% <0.00%> (ø)
src/shared/types.ts	0.00% <0.00%> (ø)
... and 1 more

... and 4 files with indirect coverage changes

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[github-actions]

🎉 This is included in version v1.32.0 🎉

The release is available on:

• GitHub releases
• npm package (@latest dist-tag)

Cheers! 📦🚀