feat(enterprise): scope knowledge stores

[Gracker]

Summary

• add scoped enterprise knowledge persistence over memory_entries for RAG, baseline, project memory, case library, and case graph
• pass RequestContext/analysis scope through admin routes, CI baseline reads, Claude/OpenAI MCP tools, and runtime pattern/SQL-learning paths
• filter candidates by tenant/workspace before RAG, project-memory, case, and analysis-pattern recall; keep system RAG knowledge available via system/system scope
• add enterprise scope isolation coverage and mark README §0.3.7 complete

Verification

• PATH="$HOME/.nvm/versions/node/v24.15.0/bin:$PATH" npm run typecheck (backend)
• PATH="$HOME/.nvm/versions/node/v24.15.0/bin:$PATH" npx jest --runInBand --forceExit src/services/tests/enterpriseKnowledgeScope.test.ts src/agentv3/tests/analysisPatternMemory.test.ts src/services/tests/ragStore.test.ts src/services/tests/baselineStore.test.ts src/agentv3/tests/projectMemory.test.ts src/services/tests/caseLibrary.test.ts src/services/tests/caseGraph.test.ts src/routes/tests/ragAdminRoutes.test.ts src/routes/tests/baselineRoutes.test.ts src/routes/tests/caseRoutes.test.ts src/routes/tests/memoryRoutes.test.ts src/routes/tests/ciGateRoutes.test.ts (backend)
• PATH="$HOME/.nvm/versions/node/v24.15.0/bin:$PATH" npm run test:core (backend)
• git diff --check
• PATH="$HOME/.nvm/versions/node/v24.15.0/bin:$PATH" npm run test:scene-trace-regression (backend)
• PATH="$HOME/.nvm/versions/node/v24.15.0/bin:$PATH" npm run verify:pr