Server-side interactive segmentation and stereo for the web client

[mattdawkins]

Draft. Runs the web client's interactive SAM segmentation and stereo point mapping in VIAME's interactive_service on the server GPU instead of ONNX in the browser (the alternative to #1672 discussed earlier).

Server

• dive_interactive broker (new compose service interactive, GPU profile, same worker image): spawns one viame.core.interactive_service process per user+dataset session, matches its out-of-order replies by id, keeps disparity_ready events for polling
• Load limits so many segmentation / mapping requests cannot crowd the GPU: DIVE_INTERACTIVE_MAX_SESSIONS resident processes (idlest evicted), DIVE_INTERACTIVE_IDLE_SECONDS retirement, DIVE_INTERACTIVE_MAX_INFLIGHT inferences at once, and a request that cannot get a turn within DIVE_INTERACTIVE_QUEUE_TIMEOUT is refused with 503 rather than queued
• Girder dive_interactive resource: segmentation/predict, segmentation/keypoints, segmentation/stereo_segment, text_query, stereo/{set_frame,transfer_points,transfer_line,measure_line,aggregate_lengths}, DELETE session. Resolves dataset/camera/frame to assetstore paths (image sequences and transcoded video with frame time; large-image datasets rejected) and the calibration item; the interactive container mounts the assetstore read-only
• Gating: the tools are paused (503 and interactiveEnabled: false in dive_configuration) while any pipelines / training / private-queue job is queued or running, since they share the GPU
• Tests: session manager against a fake service process (deferred replies, events, busy refusal, eviction, reaping, crash recovery) and the gate

Client (web)

• useServerSegmentation: hooks the shared point-segmentation recipe to the server (Segment tool now works on web) and carries a finished mask to the other stereo camera via the service's stereo_segment
• StereoServerMatcher: every stereo method (ncc, dino, foundation) runs through the server while it is up; the browser ONNX matchers remain the fallback. dino becomes selectable on web when the server offers it
• useConfig gains the interactive capability and re-checks it when a viewer opens

Not yet done / to discuss

• Text query and refine are exposed server-side but not wired into the web UI
• Auto-populate of new boxes/lines on web (as Add SAM2/SAM3 browser segmentation and stereo auto-population #1672 does client-side) is not wired
• Not run against a real GPU deployment yet; the worker image needs verifying that viame.core.interactive_service and the SAM / stereo add-on configs resolve under /tmp/addons/extracted
• Frame pixels are still fetched by the browser before a server warp (harmless, wasteful)

🤖 Generated with Claude Code

[BryonLewis]

With #1672 merged, DIVE Web already has point-prompt SAM segmentation and stereo auto-population running in the browser (ONNX / WebGPU with WASM fallback). That covers the interactive web workflow this PR was standing in for.

I don’t think we need the server-side interactive broker / Girder proxy path anymore for that purpose, it adds GPU-host ops, long-lived sync request handling, and session management we can avoid now that the client path is in main.

Happy to close this as superseded by #1672 unless there’s a separate reason to keep a VIAME-parity / server-GPU option (shared GPU with pipelines, weak clients, exact desktop service parity, etc.). If so, we can reopen or split that out later; otherwise I’ll close this draft.