Add one-click install script with automatic secret generation

- Create scripts/install.sh that auto-generates Ed25519 signing key,
  JWT secret, Postgres and MinIO passwords from .env.example placeholders
- Add startup validation in server to reject placeholder secrets
- Add 401 interceptor in console API client to clear stale JWT tokens
- Update README Quick Start to use ./scripts/install.sh
- Update .env.example with GENERATE_ME placeholders for all secrets

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.env.example

@@ -1,18 +1,18 @@
 # PostgreSQL
 POSTGRES_USER=elydora
-POSTGRES_PASSWORD=elydora-secret-change-me
+POSTGRES_PASSWORD=GENERATE_ME
 POSTGRES_DB=elydora
-DATABASE_URL=postgresql://elydora:elydora-secret-change-me@postgres:5432/elydora
+DATABASE_URL=postgresql://elydora:GENERATE_ME@postgres:5432/elydora
 
 # Redis
 REDIS_URL=redis://redis:6379
 
 # MinIO
 MINIO_ROOT_USER=elydora
-MINIO_ROOT_PASSWORD=elydora-minio-secret-change-me
+MINIO_ROOT_PASSWORD=GENERATE_ME
 MINIO_ENDPOINT=http://minio:9000
 MINIO_ACCESS_KEY=elydora
-MINIO_SECRET_KEY=elydora-minio-secret-change-me
+MINIO_SECRET_KEY=GENERATE_ME
 MINIO_BUCKET=elydora-evidence
 
 # Elydora API
@@ -20,8 +20,8 @@ PORT=8787
 ENVIRONMENT=production
 API_VERSION=v1
 PROTOCOL_VERSION=1.0
-JWT_SECRET=change-me-to-a-random-string-at-least-32-chars
-ELYDORA_SIGNING_KEY=change-me-base64url-ed25519-private-key
+JWT_SECRET=GENERATE_ME
+ELYDORA_SIGNING_KEY=GENERATE_ME
 ALLOWED_ORIGINS=http://localhost:3000
 
 # TSA (optional)