build: format package repository as object metadata

[zimeg]

Summary

• Formats the repository field in package.json as a full object with type and url properties, replacing the shorthand string "slackapi/bolt-js"
• This follows the npm package.json repository specification and ensures compatibility with tools that expect the object format

Test plan

• Verified with npm pkg fix that this matches npm's normalized format
• Confirm npm test passes with no changes to build/test behavior

Co-Authored-By: Claude svc-devxp-claude@slack-corp.com
🤖 Generated with Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.59%. Comparing base (2235635) to head (0343ba3).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2850   +/-   ##
=======================================
  Coverage   93.59%   93.59%           
=======================================
  Files          44       44           
  Lines        7853     7853           
  Branches      686      686           
=======================================
  Hits         7350     7350           
  Misses        498      498           
  Partials        5        5           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[zimeg]

📣 Fixes a warning from recent publish #2848:

npm warn publish npm auto-corrected some errors in your package.json when publishing.  Please run "npm pkg fix" to address these errors.
npm warn publish errors corrected:
npm warn publish "repository" was changed from a string to an object
npm warn publish "repository.url" was normalized to "git+https://github.com/slackapi/bolt-js.git"