docs: sync from frontend 9013b70 — staged node-package upgrade + TS6 test fix + lint sweep

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

09 - Audits/Activity Log.md

@@ -11,6 +11,26 @@ entries on top. Maintained by agents per the rule in `../AGENTS.md`.
 
 ---
 
+### 2026-05-30 — frontend@9013b70, c77cf82, 8add494 — staged node-package upgrade + TS6 test fix + lint sweep
+
+**Commits:** `8add494` `c77cf82` `9013b70`
+**Touched:**
+- Deps (`package.json`, `yarn.lock`): TypeScript 5→6, Jest 29→30, Tiptap 2→3 (all 11 sub-packages), i18next 25→26, react-i18next 15→17, @types/node 22→25, @types/jest 29→30, react-dropzone 14→15, react-apexcharts 1→2, mui-one-time-password-input 5→7, React 19.1→19.2, MUI 7.1→7.3 (in-range), zod 4.0→4.4. Constraints bumped to tested floors (`@mui/material ^7.3.11`, `wagmi ^2.19.5`, etc.). Version bumped 2.7.9 → 2.7.10.
+- Code fixes for new types: `src/theme/with-settings/update-core.ts` (cast `currentScheme` via `Record<string,unknown>` after MUI 7.3 tightened `ColorSystemOptions`), `src/components/editor/components/code-highlight-block.tsx` (cast `NodeViewContent as='code'` → `'code' as 'div'` for Tiptap 3 stricter prop typing).
+- Test infra: `jest.config.js` (point ts-jest at `tsconfig.test.json` explicitly, ignore TS5101/TS5011), `tsconfig.test.json` (add `rootDir: "."` and `ignoreDeprecations: "6.0"`).
+- Security hygiene: `.env.local` + `.env.production` removed from tracking; added to `.gitignore`. Existing values still in git history — rotate any leaked credentials.
+- Lint sweep: `yarn lint:fix` applied across 64 files in `src/` — mostly `perfectionist/sort-imports` reorders and unused-imports removals.
+- Docs: `AGENTS.md` gained an "Enforced project conventions" section covering Prettier, ESLint, TypeScript, and the centralized `src/theme/` structure. `CLAUDE.md` is now a symlink → `AGENTS.md` so Claude Code reads the same rules.
+- Tooling: `scripts/upgrade-packages.sh` (reusable staged-upgrade runner with snapshot + auto-rollback) and `scripts/UPGRADE-PLAN.md` (strategy + per-stage rationale) added. `.upgrade-backups/` added to `.gitignore`.
+
+**Why:** Many runtime / dev dependencies were 3–7 minors behind; the audit was triggered by a request to "update all node packages without breaking the build." Did it as eight staged groups (in-range → @types → ESLint → Jest → Tiptap → i18next → misc → TypeScript), each gated by `yarn build`. Three stages were pulled back: ESLint 10 (eslint-plugin-react@7 incompatible with new context API), wagmi 3 (@coinbase/wallet-sdk declares `window.ethereum: unknown`, breaks type union with viem), MUI 7→9 (AGENTS.md pins to v7).
+
+**Verification:** `yarn build` passes after every stage (34–44s, all 57 routes). `yarn test` recovered from "45 suites fail, 0 tests run" (TS6 blocker) to 530 tests pass, 18 unrelated mock failures. `yarn lint` went 204 → 21 problems (the remaining 5 errors are pre-existing: 2× `@ts-nocheck`, 3× `no-bitwise`). Dev server (`/`, `/auth/jwt/sign-in`, `/post`, `/shop`, `/dashboard`, `/telegram`) all return 200. Manual smoke test of the Tiptap editor + wagmi connect flow is still recommended before promoting to prod.
+
+**Linked docs updated:** none yet — `07 - Development/` should grow a "Node dependency upgrade runbook" pointing at `frontend/scripts/UPGRADE-PLAN.md` and the staged-rollback pattern. Also worth promoting the new AGENTS.md conventions section to `07 - Development/Coding Standards.md`.
+
+---
+
 ### 2026-05-29 — backend@cdc8df1 — AMN Pay Scanner integration (retire Request Network)
 
 **Commits:** backend `cdc8df1`, scanner `8fee27e`