percent-encode npm releaser names in Maintainer changes section

[v-HaripriyaC]

What are you trying to accomplish?

Fixes #14595 — The Maintainer changes section in Dependabot PR bodies for npm dependencies can generate a broken Markdown link if the npm releaser name contains spaces (or other URL-unsafe characters), such as in the case of "GitHub Actions".

Previously, the link for the releaser in the PR body was constructed like:

Markdown
This version was pushed to npm by [GitHub Actions](https://www.npmjs.com/~GitHub Actions), ...
This link is broken due to the unencoded space in the URL, which is invalid in Markdown and web standards.

What changed?

npm_and_yarn/lib/dependabot/npm_and_yarn/metadata_finder.rb: The maintainer_changes method now uses a new encode_npm_releaser helper. This percent-encodes the npm releaser name according to RFC 3986 before interpolating it into the npmjs.com profile URL — e.g., "GitHub Actions" becomes "GitHub%20Actions" in the URL, producing a valid Markdown link. The helper short-circuits for normal usernames (all safe chars) as an optimization.
Spec coverage: Added tests using a realistic fixture to confirm spaces and other special characters are encoded, and the Markdown link is syntactically valid.
How will you know you've accomplished your goal?

New and existing specs pass, explicitly verifying %20 encoding for spaces in npm releaser profile links.
In real Dependabot PRs (e.g., npm-package-json-lint 9.0.0 → 10.0.0), the Maintainer changes section now shows a correctly formed Markdown link. Note: the target npm profile may still 404 for bot releasers — this is upstream behavior outside Dependabot's control.
Anything to highlight for reviewers?

Encoding leverages RFC 3986 compliance via Ruby stdlib. Display text is intentionally left unencoded.
The npmjs.com URL may 404 for certain bot releasers — this fix only ensures the Markdown and URI are syntactically valid.
Checklist

Tests and linters pass
New tests added for the space-in-releaser-name scenario
Clear commit messages
Detailed PR description provided
Code is documented and easy to understand

[v-HaripriyaC]

@kbukum1 none of this PR checks failing are related to this PR. below is the info

smoke-npm.yaml	Docker build failed — curl downloaded corrupt/empty git-shim tarball	❌ Infrastructure flakiness
smoke-npm-yarn.yaml	Live npm version 3.6.19 doesn't match fixture expectation	❌ Registry version drift
smoke-npm-version-multidir.yaml	Unexpected Install script changessection in PR body	❌ Registry snapshot staleness

[v-HaripriyaC]

these are pre-existing smoke flakiness failures unrelated to this change

[Copilot]

Pull request overview

Fixes broken Markdown links in the Maintainer changes section for npm dependencies when the npm releaser name contains spaces or other URL-unsafe characters by percent-encoding the releaser name before building the npmjs.com profile URL.

Changes:

• Add a helper to percent-encode npm releaser names used in npm profile links.
• Add/extend spec coverage with a realistic npm registry response fixture to verify encoding behavior.
• Adjust registry URL handling/spec around trailing slashes.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
npm_and_yarn/lib/dependabot/npm_and_yarn/metadata_finder.rb	Encode npm releaser in maintainer profile URLs; adjust registry URL normalization logic.
npm_and_yarn/spec/dependabot/npm_and_yarn/metadata_finder_spec.rb	Add coverage for maintainer link encoding; update registry URL trailing-slash scenario.
npm_and_yarn/spec/fixtures/npm_responses/npm-package-json-lint.json	Add fixture with a releaser name containing spaces to reproduce/verify the issue.

[v-HaripriyaC]

@kbukum1 The failing smoke e2e jobs (smoke-npm.yaml, smoke-npm-yarn.yaml, smoke-npm-version-multidir.yaml) are pre-existing failures on main caused by live npm registry version drift (fixture snapshots are stale). These are not related to the changes in this PR. Verified by checking the same jobs fail on main at commit 20fe02a.