fix(repo): make --limit cap total results

[ychampion]

Summary

• Cap repo list --limit output after the repo service returns results.
• Keep repo search --limit as both SearchRepoOpts.Limit and PerPage, then cap output after the search call.
• Cover both paths with CLI tests that return more repos than the limit and assert the printed row count.

Why

Fixes #133. --limit should cap the total number of repositories printed. Search still uses the limit as the backend page size because the current search backends fetch one page.

Validation

• go test ./internal/cli -run 'TestRepo(List|Search)LimitCapsTotalResults' -count=1
• go test ./internal/cli -count=1
• go test ./... -count=1
• git diff --check

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Pull request overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

[andrew]

Thanks for picking this up. As written this doesn't fix #133 and regresses repo search:

• No backend reads ListRepoOpts.Limit or SearchRepoOpts.Limit (see github/github.go:105,402, gitlab/gitlab.go:95,388, gitea/gitea.go:102,365, bitbucket/bitbucket.go:210). FilterRepos in forge.go doesn't apply it either. So repo list --limit N still returns everything.
• Search on every backend fetches a single page sized by PerPage. Removing PerPage: flagLimit means --limit 5 now returns 30 results instead of 5.

Please apply the two changes below so --limit actually caps output, and update the tests to prove it by returning more repos than the limit and checking the printed count. Stopping backend pagination early can be a follow-up.