fix: [PRODUCT-503] show user all available zones

[sigmachirality]

We want to show users all zones even if some are currently sold out.

[semanticdiff-com]

Review changes with  

Changed Files

File	Status
src/lib/zones.tsx	20% smaller

[greptile-apps]

Greptile Summary

This PR modifies the zones display functionality in the CLI to provide users with visibility into all available infrastructure zones, including those that are currently sold out. The changes include:

1. Updating type definitions to be more precise (ZonesListResponse type now uses a literal "list")
2. Removing the retired zones filter that previously hid certain zones from users
3. Making the CLI documentation more dynamic by using the first actually available zone in examples instead of hardcoding 'alamo'

This change improves transparency by giving users complete information about all zones in the system, allowing them to make better-informed decisions about resource allocation.

Confidence score: 4/5

1. This PR is safe to merge with minimal risk of breaking existing functionality
2. The changes are straightforward, well-typed, and improve user experience without modifying core business logic
3. Pay attention to src/lib/zones.tsx to ensure the removal of zone filtering doesn't have unintended side effects in zone selection workflows

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