refactor: migrate to api-server library pattern

[joshuasequeira19]

Replace direct Kubernetes access with api-server service library for unified business logic across CLI and API server.

Changes

Architecture

• Replace pkg/k8s with pkg/workspace wrapper service
• Import api-server/pkg/services/forkspacer as library
• All commands delegate to api-server for business logic
• Add Get() and List() methods in wrapper (api-server missing these)

Commands Refactored

• create: Uses service.Create() with proper waitForWorkspaceReady polling
• list: Uses service.List() with namespace filtering support
• get: Uses service.Get()
• delete: Uses service.Delete()
• hibernate: Uses service.SetHibernation(true)
• wake: Uses service.SetHibernation(false)

Code Quality

• Simplified codebase: -178 net lines of code
• Fixed 3 go vet errors (non-constant format strings)
• Updated to Go 1.25
• Added Makefile for build automation
• Improved waitForWorkspaceReady with proper polling and error detection

Documentation

• Updated README architecture section
• Documented api-server library pattern
• Fixed project structure (removed pkg/k8s references)
• Updated development prerequisites to Go 1.25

CI/CD

• Updated workflow to Go 1.25
• Removed -race flag (Go 1.25 compatibility)
• Simplified test execution

Benefits

• Single source of truth for workspace operations
• Type-safe compile-time checking
• No code duplication for business logic
• Consistent validation and error handling
• No network overhead (direct library calls)

Breaking Changes

• Removed pkg/k8s (replaced by pkg/workspace)
• Added dependency on api-server v1.0.0
• Requires Go 1.25 (updated from 1.24)

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