fix(pipeline): harden intercept, tap, and download steps

[Astro-Han]

Description

Harden the intercept, tap, and browser-assisted download pipeline steps so transient browser disconnects can recover consistently.

This PR now covers three concrete behaviors:

• add retry coverage for browser-backed intercept, tap, and download steps
• throw clear ConfigError failures when browser-only steps run without a page
• keep public downloads working when cookie access is flaky, while still retrying protected downloads that fall back to login/error HTML pages

Related issue:

• none found

Type of Change

• 🐛 Bug fix
• ✨ New feature
• 🌐 New site adapter
• 📝 Documentation
• ♻️ Refactor
• 🔧 CI / build / tooling

Checklist

• I ran the checks relevant to this PR
• I updated tests or docs if needed
• I included output or screenshots when useful

Documentation (if adding/modifying an adapter)

• Added doc page under docs/adapters/ (if new adapter)
• Updated docs/adapters/index.md table (if new adapter)
• Updated sidebar in docs/.vitepress/config.mts (if new adapter)
• Updated README.md / README.zh-CN.md when command discoverability changed
• Used positional args for the command's primary subject unless a named flag is clearly better
• Normalized expected adapter failures to CliError subclasses instead of raw Error

Screenshots / Output

npx tsc --noEmit
npx vitest run src/

Test Files  27 passed (27)
Tests       286 passed (286)

[Astro-Han]

Closing to redo with a cleaner approach. Will reopen with a fresh PR.