chore: initialize repository with project rules, docs, and phase-1 ADRs

Set up the foundation for the adastra-portal project:

- CLAUDE.md captures durable project rules (quality bar, security/perf/a11y
  as first-class, language, commit conventions, ADR proactivity).
- docs/ and decisions/ scaffolding with maintained indexes (docs/README.md
  and decisions/README.md), MADR 4.0.0 template, and tag vocabulary.
- Phase-1 ADRs (0001-0006) lock structural choices: ADR usage, Nx monorepo
  with the apps preset, naming convention (adastra-portal / portal-shell /
  portal-bff), Angular CSR/zoneless/Signals/Vitest, NestJS over Express,
  PostgreSQL with Prisma.
- docs/setup/ guides translated to English.
- .gitignore covers Node/Nx artifacts and the personal notes/ scratchpad.

The Nx workspace itself is not yet bootstrapped; that step is gated on a
revised setup guide aligned with the ADRs.

docs/setup/03-angular-nx-monorepo.md

@@ -0,0 +1,116 @@
+# 🏗️ Angular monorepo with Nx + pnpm
+
+> ⚠️ This guide is **pending revision**: the placeholder workspace name (`my-workspace`) and app name (`web`) must be replaced with project-specific values, and the procedure must be extended to cover the Node API / BFF side. Treat the steps below as a baseline only.
+
+## Goal
+
+Create a scalable and maintainable architecture.
+
+---
+
+## 1) Workspace creation
+
+```bash
+cd ~/dev
+
+pnpm dlx create-nx-workspace@latest my-workspace \
+  --preset=angular-monorepo \
+  --pm=pnpm \
+  --appName=web \
+  --style=scss \
+  --routing=true \
+  --unitTestRunner=vitest
+```
+
+---
+
+## 2) Recommended layout
+
+```text
+apps/
+  web/
+
+libs/
+  shared/ui/
+  shared/data-access/
+  shared/util/
+  feature/auth/
+```
+
+---
+
+## 3) Generate libraries
+
+```bash
+pnpm nx g @nx/angular:library shared-ui
+pnpm nx g @nx/angular:library feature-auth
+```
+
+---
+
+## 4) Main commands
+
+```bash
+pnpm nx serve web
+pnpm nx build web
+pnpm nx test web
+pnpm nx lint web
+```
+
+---
+
+## 5) Workspace-wide commands
+
+```bash
+pnpm nx run-many -t lint test build
+pnpm nx affected -t lint test build
+```
+
+---
+
+## 6) Prettier
+
+`.prettierrc`:
+
+```json
+{
+  "singleQuote": true,
+  "semi": true,
+  "printWidth": 100
+}
+```
+
+---
+
+## 7) Git hooks
+
+```bash
+pnpm add -D husky lint-staged
+pnpm exec husky init
+```
+
+---
+
+## 8) CI/CD
+
+> ⚠️ The original procedure targeted GitLab CI. The project repository now lives on Gitea, so this section needs to be rewritten for Gitea Actions (or the chosen CI runner). Tracked under the next round of CI ADRs.
+
+---
+
+## 9) Daily workflow
+
+```bash
+pnpm install
+pnpm start
+pnpm nx g component login
+pnpm nx affected -t lint test build
+```
+
+---
+
+## Result
+
+* Scalable monorepo
+* Optimized builds
+* Fast CI
+* Clear architecture