feat: initial API skeleton — routes, controllers, migrations, deploy docs

Implements the JSON API for Le Donut Infolab per INSTRUCTIONS.md.

Schema (migrations/001-002):
  - 8 tables: categories, members, projects, project_members, roadmap_steps,
    discussions, resources, activity_log
  - 6 categories seeded with colors / dimensions (social, ecologique, transversal)
  - FK contraintes + soft delete sur projects, CHECK sur progress_percent

Bare PHP framework (src/):
  - Front controller public/index.php + router :params + auth flag par route
  - PSR-4 autoload sans Composer (bootstrap.php)
  - Database PDO singleton + helpers fetchOne/All/insert/update/delete
  - Validator fluent -> 422 {error: validation_failed, fields: {...}}
  - Bearer token admin (hash_equals) sur POST/PATCH/DELETE
  - Slugger avec unicité (suffixe -2, -3...) via intl Transliterator
  - ActivityLogger best-effort sur activity_log
  - Erreurs uniformes : 400/401/404/405/409/422/500 + CORS configurable

10 contrôleurs (Health, Categories, Members, Projects, ProjectMembers,
Roadmap, Discussions, Resources, Activity, Stats). Transitions de statut
loggées (created_project, completed_step, joined, etc.).

Cible prod :
  - Dockerfile (php:8.3-apache + pdo_mysql + intl + opcache)
  - docker-compose.yml sur réseau donut-net, bind 127.0.0.1:8003
  - caddy.conf pour infolab.ledonut-marseille.org
  - migrations/apply.sh idempotent (table schema_migrations)
  - DEPLOY.md avec commandes SSH exactes

Tests :
  - tests/smoke.sh exerce 10 endpoints clés, body envoyé via stdin
    (--data-binary @-) pour gérer l UTF-8 sous Git Bash Windows.

Vérifié localement sous Laragon Apache + MySQL 8.4 : 10/10 OK + cas
négatifs (401, 404, 405, 409, 422) conformes au contrat.

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

docker-compose.yml

@@ -0,0 +1,20 @@
+services:
+  donut-infolab:
+    build:
+      context: .
+      dockerfile: Dockerfile
+    container_name: donut-infolab
+    restart: unless-stopped
+    networks:
+      - donut-net
+    ports:
+      - "127.0.0.1:8003:80"
+    env_file:
+      - /srv/donut/secrets/infolab.env
+    volumes:
+      - /srv/donut/web/infolab:/var/www/html
+    depends_on: []
+
+networks:
+  donut-net:
+    external: true