Move cloud object models to separate crate.

[vorporeal]

Description

Moves the remaining low-level cloud object model definitions out of the app crate so they can be reused outside warp without pulling in app-specific code.

This PR moves the workflow enum and cloud environment model surfaces into the server/client cloud object layer while keeping compatibility re-exports for existing app call sites. This is a preparatory step toward extracting the shared cloud object substrate and model crates in the follow-up PRs.

Linked Issue

None.

Testing

• cargo check --manifest-path /Users/david/src/warp/Cargo.toml -p warp --tests

No manual app testing; this is a crate-boundary refactor with no intended product behavior changes.

Agent Mode

• Warp Agent Mode - This PR was created via Warp's AI Agent Mode

CHANGELOG-NONE

Co-Authored-By: Oz oz-agent@warp.dev

[vorporeal]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
Learn more

• Extract CloudObject client and models to separate crates. #11166
• Create cloud_objects crate. #11165
• Move cloud object models to separate crate. #11164 👈 (View in Graphite)
• Move GenericStringModel to warp_server_client. #11117
• Move GenericCloudObject to warp_server_client. #11115
• Move GenericServerObject to warp_server_client. #11114
• Move some types to the warp_server_client crate. #11113
• Delete unused new_from_server_update function. #11112
• master

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