test(web): add Vitest CI, ADRs, and PR Definition of Done

FE unit-тесты селекторов/api-client в CI; ADR по durable jobs, OpenAPI codegen и legacy Svelte; PR template WEB-19; процесс KPI cross-app sync.

Co-authored-by: Cursor <[email protected]>

docs/adr/003-legacy-svelte-removal.md

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+# ADR-003: Removal of web-legacy-svelte
+
+## Status
+
+Accepted (2026-07)
+
+## Context
+
+`web-legacy-svelte/` (~294 files) confused agents/codegraph after the React + ReUI migration to `apps/web/`.
+
+## Decision
+
+Delete `web-legacy-svelte/` from `main`. Historical reference remains in git history. Docs and `AGENTS.md` point only to `apps/web/`.
+
+## Consequences
+
+No Svelte imports allowed. Restore from git history if a one-off migration reference is needed.