Move GenericCloudObject to warp_server_client.

[vorporeal]

Description

Moves GenericCloudObject into warp_server_client while keeping app-local cloud object behavior in warp.

The upstream type now owns the portable data/container behavior: model accessors, constructors, server update/conflict handling, and portable upsert params. The app crate continues to own CloudObject, CloudModelType, persistence events, queue behavior, UI/Drive integration, and other runtime-specific logic.

This also adds app-local lookup extension traits so type aliases can keep readable calls like CloudAmbientAgentEnvironment::get_all(ctx), CloudScheduledAmbientAgent::get_by_id(...), and CloudMCPServer::get_by_uuid(...) without duplicating helper functions or making the upstream crate depend on AppContext/CloudModel.

Testing

Validated on the stack tip after Phase 3:

• cargo fmt --manifest-path /Users/david/src/warp/Cargo.toml --all
• cargo check --manifest-path /Users/david/src/warp/Cargo.toml -p warp_server_client
• cargo check --manifest-path /Users/david/src/warp/Cargo.toml -p warp
• cargo check --manifest-path /Users/david/src/warp/Cargo.toml -p warp --tests
• git --no-pager diff --check

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
• 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 👈 (View in Graphite)
• 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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