Add prefill decode endpoint mode

[Levi080513]

Summary

• Add Standard and Prefill / Decode deployment modes for endpoint create/edit flows.
• Add P/D role tabs for Prefill and Decode replicas, resources, environment variables, and engine args.
• Keep Model Settings and Engine Settings as standalone sections, and place endpoint Replica Settings after Engine Settings for both Standard and P/D modes.
• Normalize P/D submit payloads to strategy pd, same-host role placement, spec.replicas.num, and role-level replicas/resources/env/variables, while stripping P/D-only fields from standard payloads.
• Remove KV Settings from the phase 1 UI and payload.
• Show endpoint status.replicas[] as the only ReplicaStatus list in the Status tooltip, without role summary.
• Update endpoint types, locales, i18n tracking, and focused unit coverage.

Tests

• yarn vitest run src/domains/endpoint/hooks/use-endpoint-form.test.tsx
• yarn vitest run src/domains/endpoint/components/EndpointStatus.test.tsx src/domains/endpoint/hooks/use-endpoint-form.test.tsx src/domains/endpoint/lib/endpoint-form-helpers.test.ts
• yarn test
• yarn build
• yarn biome lint src/domains/endpoint/hooks/use-endpoint-form.tsx src/domains/endpoint/hooks/use-endpoint-form.test.tsx src/locales/en-US.json
• yarn biome lint src/domains/endpoint/components/EndpointStatus.tsx src/domains/endpoint/components/EndpointStatus.test.tsx src/foundation/components/BaseStatus.tsx src/domains/endpoint/types.ts src/locales/en-US.json
• node tools/i18n-tracker.cjs
• node tools/check-i18n-keys.cjs
• curl -I --max-time 5 http://127.0.0.1:5174/

Notes

• Live Neutree E2E/TestRail validation was not run in this session because no live environment was configured. Please run the endpoint create-form E2E flow against a deployed control plane before marking ready.
• Browser automation was unavailable in the latest session; local dev server load was verified by HTTP 200 from http://127.0.0.1:5174/.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 73.89163% with 53 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
src/domains/endpoint/hooks/use-endpoint-form.tsx	59.20%	44 Missing and 7 partials ⚠️
src/domains/endpoint/components/EndpointStatus.tsx	95.45%	1 Missing ⚠️
src/domains/endpoint/components/ResourcesCard.tsx	0.00%	1 Missing ⚠️

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