enhance(packages): show package count in profile tabs

[ahanoff]

Summary

• Show package counts on user and organization package tabs, matching the existing repository and project tab counters.
• Count distinct owner packages that have at least one non-internal version.
• Hide the package count badge when the count is zero.

Screenshots

Captured locally with Podman and Playwright/Chrome:

• Before:

• After:

Testing

• make GO=/home/ahanoff/.local/bin/go fmt
• /home/ahanoff/.local/bin/go test -run '^TestCountOwnerPackages$|^TestHasOwnerPackages$' ./models/packages/
• git diff --check
• make deps-frontend
• make frontend
• pnpm exec playwright screenshot --browser=chromium --channel=chrome --viewport-size=1365,768 --wait-for-timeout=1000 http://127.0.0.1:3101/demo/-/packages screenshots/package-tab-before.png
• pnpm exec playwright screenshot --browser=chromium --channel=chrome --viewport-size=1365,768 --wait-for-selector=".ui.secondary.pointing.menu .item .ui.small.label" --wait-for-timeout=500 http://127.0.0.1:3102/demo/-/packages screenshots/package-tab-after.png

AI Assistance

This PR was prepared with assistance from Codex:GPT-5.5 xhigh and reviewed before submission.

[wxiaoguang]

Actually I have objection for adding more and more "count" numbers to the tabs.

For most cases, it only slows down the page loading and most users don't need it.

That's just my personal opinion, so I won't block it if most people like it.