chore(tests): consolidate test patterns — shared Vitest base, central @sim/testing mocks, check:test-patterns, lean agent docs - #8309

Summary

• One shared Vitest base (vitest.shared.ts): every workspace config extends it; clearMocks, restoreMocks, unstubEnvs, unstubGlobals are on (integration mode keeps per-file fixtures), globals: true removed. ~450 redundant vi.clearAllMocks/restoreAllMocks/unstubAll* hook calls deleted
• @sim/testing is now the single home for mocks: ~220 central mocks (xMock + xMockFns, full export surface, faithful enums/error classes) and shared helpers (jsonResponse, createRouteContext, createDeferred, flushMicrotasks, collectStream, principal factories). ~2,300 hand-rolled vi.mock factories and ~600 inline principals across ~1,900 test files now use them
• Global mocks extended so tests stop re-mocking them: @sim/db re-exports every schema table, @trigger.dev/sdk task() returns its config (+ runs.*, idempotencyKeys, AbortTaskRunError), drizzle sql is a spy, getMockLogger(name), stable telemetry spies. schemaMock table names are generated from packages/db/schema.ts (check:schema-mock guards drift)
• New check:test-patterns audit (in check:audits): fails on a new local factory for a centrally mocked module, a re-mock of a global module, a local copy of a shared helper, a redundant hook, or a __tests__/ dir. Ratchet baseline holds the 145 deliberate exceptions (per-test component stand-ins, real-SQL inspection, …)
• Naming: tests sit next to their source and are named after it — __tests__//tests/ dirs colocated, 26 topic-split files merged into their source's test
• Every integration suite goes through the shared TEST_DATABASE_URL/TEST_REDIS_URL contract (IPv6 loopback works, credentialed Redis rejected); the OAuth token integration test no longer leaves a rate-limit bucket behind
• Folds in the still-applicable v0.9.2: resource dropdown in org view, new library posts, removed unnecessary tests #8303 review feedback: typed condition-handler fixtures, restored MCP same-author secret-retention case, shared DB guard; declined the clearMocks-off claims (Vitest 5 default, now explicit in config) and the DB-name/test-rule suggestions
• Agent docs made lean and consistent: root CLAUDE.md 484 → ~140 lines, global.md folded in, API rules in one sim-api-contracts.md, apps/sim/AGENTS.md → pointer, contradictions fixed (comments, hooks example, emcn paths, canvas sentences, repo tree). sim-testing.md 365 → 165 lines (mock table → discovery rule). One run command everywhere (bun run --cwd <ws> test); /ship and /cleanup gate tests through test-audit
• Fixes: generate-docs no longer reads mock descriptions from test files into the integration catalog; path-independent secret-leak checks in knowledge-processing; best-of-three scaling ratio for the chat-content linearity checks

Type of Change

• Other: test infrastructure, tooling, docs

Testing

• bun run test (every workspace): apps/sim 34,269 passed; only failure was a pre-existing sim-cli lock-timing flake that passes 3/3 alone
• bun run test:integration (Docker Postgres + Redis): apps/sim 96 files / 926 tests, packages/db 14 / 95 — all pass
• bunx turbo run type-check 26/26, bun run lint, bun run check:audits (51), docs-manifest:check, block registry, check:migrations

Checklist

• Code follows project style guidelines
• Self-reviewed my changes
• Tests added/updated and passing (new tests pass the test-audit authoring gate)
• No new warnings introduced
• I confirm that I have read and agree to the terms outlined in the Contributor License Agreement (CLA)