Extract CloudObject client and models to separate crates.

[vorporeal]

Description

Extracts the concrete cloud object model layer and object client interface into dedicated crates so future cloud sync work can depend on them without depending on the full app crate.

This PR adds cloud_object_models for concrete server/model types and cloud_object_client for ObjectClient, object update messages, initial load responses, permissions/action result types, and related client-facing surfaces. The app and warp_server_client retain compatibility shims/re-exports while call sites are updated to use the extracted crates where appropriate.

The PR also moves model-only tests into cloud_object_models and restores docs/comments that were accidentally dropped during the migration.

Linked Issue

None.

Testing

• cargo fmt --manifest-path /Users/david/src/warp/Cargo.toml --all
• cargo check --manifest-path /Users/david/src/warp/Cargo.toml -p cloud_object_models -p cloud_object_client
• cargo check --manifest-path /Users/david/src/warp/Cargo.toml -p cloud_object_models -p warp --tests
• cargo nextest run --manifest-path /Users/david/src/warp/Cargo.toml -p cloud_object_models
• HOME=$(mktemp -d) cargo nextest run --manifest-path /Users/david/src/warp/Cargo.toml -p warp

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 cloud object persistence logic to other crates. #11179
• Extract CloudObject client and models to separate crates. #11166 👈 (View in Graphite)
• Create cloud_objects crate. #11165
• Move cloud object models to separate crate. #11164
• 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

This stack of pull requests is managed by Graphite. Learn more about stacking.