refactor(utils): extract route URL builders into shared paths.ts

[fansilas]

Summary

PR detail (/miners/pr?repo=&number=) and repository detail (/miners/repository?name=) URLs were being hand-built in 14 places across the app, each with its own encodeURIComponent boilerplate. This PR introduces src/utils/paths.ts exposing two helpers, minerPrPath and minerRepositoryPath, and routes every existing call site through them. Output is byte-identical to the previous inline strings (param order, encoding, and casing all preserved), so navigation behaviour is unchanged.

Two pre-existing oddities surfaced during the sweep. Both are left inline with a TODO and intentionally excluded from this PR so the extraction stays a no-op:

• src/pages/HomePage.tsx links to /repositories/details?repo=..., which is not a registered route in src/routes.tsx (only /miners/repository exists). Looks like a latent 404 bug rather than a second route variant.
• src/pages/dashboard/views/LiveCommitLog.tsx builds the PR href without encodeURIComponent, so adopting the helper would change the URL string. Worth converting in a follow-up.

Related Issues

N/A

Type of Change

• Bug fix
• New feature
• Refactor
• Documentation
• Other (describe below)

Screenshots

Not applicable. No rendered UI changes; only the internal source of route href strings is moving.

Checklist

• New components are modularized/separated where sensible
• Uses predefined theme (e.g. no hardcoded colors)
• Responsive/mobile checked
• Tested against the test API
• npm run format and npm run lint:fix have been run
• npm run build passes
• Screenshots included for any UI/visual changes