chore: Create new workspace package

[lukemassa]

what

Move workspace-related types from server/events to new subpackage server/events/workspace.

Moved:

• WorkingDir interface
• WorkingDirLocker interface
• FileWorkspace struct
• GithubAppWorkingDir struct

why

I noticed that there were two different mocks being created for WorkingDir: one in events/mocks/ and another in the events package itself (mock_workingdir_test.go). It is the only mock in the project which is written into a non-mock package, leading to oddities like in #5800 where it is formatted differently (because we have different formatting rules for mock and non-mock).

The duplicate existed because project_command_builder_internal_test.go (an internal test in package events) needed to import the mock, but importing events/mocks would create an import cycle (events → events/mocks → events).

This was an indication that the workspace code was getting big enough to be its own package. Moving it to a subpackage breaks the import cycle while keeping the code organized.

tests

• go build ./...
• go test ./server/events ./server/controllers/... -short
• golangci-lint run

references

N/A

[lukemassa]

seems too heavy handed, I'll solve this another way