Adds eslint-plugin-boundaries@6.0.2 (MIT, peerDeps eslint>=6,
engines node>=18.18) as a direct devDep in apps/app/package.json,
matching the exact-pin style of the other 14 eslint-plugin-* deps.
Direct dep — not hoisted transitive — per the
TECH-PORTAL-ESLINT-DEPS lesson (Cursor's ESLint extension uses
strict module resolution and silently fails on plugins reachable
only via pnpm hoisting).
Plugin not yet enabled in .eslintrc.cjs; enabling lands in the next
commit per WS-3 1c sequence (audit Phase A → install → enable →
refactor axios.ts → docs).
Tests + typecheck verified green post-install.
Co-Authored-By: Claude <noreply@anthropic.com>