[dev] refactor devserver into a combined service model

[cjllanwarne]

Change Description

Replaces the devserver's SERVICE=... parameter with a combined service model.

Previously: SERVICE=batch gmake devserver followed by localhost:8000/
Now: gmake devserver followed by localhost:8000/batch/

Motivation:

• Allow us to test UI components from all services with a single devserver invocation.
• Allow us to build and test UI components which draw data from multiple services.

At the same time, remove the now redundant MOCK_API_DATA data generator that was used to test the flaky tests dashboard.

Security Assessment

• This change cannot impact the Hail Batch instance as deployed by Broad Institute in GCP

No prod impact. This is all client-side developer tooling.

• Required: The impact has been assessed and approved by appsec

[Copilot]

Pull request overview

This PR refactors the local devserver to run a single combined proxy that can serve multiple service UIs simultaneously (switching from a SERVICE=... model to service-prefixed URLs like /batch/, /ci/, etc.), and removes the CI MOCK_API_DATA generator path.

Changes:

• Makefile: run all UI watchers + dev proxy together without SERVICE=..., and require all relevant editable Python packages for devserver startup.
• devbin/dev_proxy.py: route by /<service>/... prefix, register service-prefixed static routes, and configure per-service Jinja environments to avoid template-name conflicts.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
Makefile	Switch devserver to a combined multi-service target set; update dependency checks and parallelism.
devbin/dev_proxy.py	Implement service-prefixed routing/static handling and multi-service Jinja setup; remove SERVICE-based branching and mock-data handler.

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[grohli]

Discussed and demo shown offline, looks great. Thanks Chris!