refactor: 统一 DB/Redis 配置为 DSN 模式 + 移除 Helm/K8s 部署

- DatabaseConfig: Host/Port/User/Password/Name/DBName/SSLMode → 单个 DSN 字段
- RedisConfig: Host/Port/Password/DB/URL → 单个 DSN 字段
- 环境变量: GOCHAT_DATABASE_* (7个) → GOCHAT_DATABASE_DSN, GOCHAT_REDIS_* (5个) → GOCHAT_REDIS_DSN
- validator.go: DSN URL 解析校验 (scheme + host)
- redis.go: redis.ParseURL(cfg.DSN) 直连
- 所有 docker-compose / CI / shell 脚本 / .env 同步更新
- 删除 deploy/helm/ 整个目录 (20个文件)
- CI 删除 helm-validate / deploy-staging / deploy-production 三个 job
- 文档同步更新 (README, 架构设计, PRD, 滚动升级)

backend/scripts/db_backup.sh

@@ -8,12 +8,21 @@ set -euo pipefail
 ENV="${1:-production}"
 TIMESTAMP=$(date +%Y%m%d_%H%M%S)
 BACKUP_DIR="${GOCHAT_BACKUP_DIR:-/var/backups/gochat}"
-DB_NAME="${POSTGRES_DB:-gochat_production}"
-DB_USER="${POSTGRES_USER:-gochat}"
-DB_HOST="${POSTGRES_HOST:-localhost}"
-DB_PORT="${POSTGRES_PORT:-5432}"
+DSN="${GOCHAT_DATABASE_DSN:-}"
 RETENTION_DAYS="${GOCHAT_BACKUP_RETENTION_DAYS:-30}"
 
+if [[ -z "$DSN" ]]; then
+    echo "[$(date)] ERROR: GOCHAT_DATABASE_DSN is not set"
+    exit 1
+fi
+
+# Parse DSN: postgres://user:password@host:port/dbname?sslmode=...
+DB_USER=$(echo "$DSN" | sed 's|.*://||; s|:.*||')
+DB_PASS=$(echo "$DSN" | sed 's|.*://[^:]*:||; s|@.*||')
+DB_HOST=$(echo "$DSN" | sed 's|.*@||; s|:.*||')
+DB_PORT=$(echo "$DSN" | sed 's|.*@.*:||; s|/.*||')
+DB_NAME=$(echo "$DSN" | sed 's|.*/||; s|\?.*||')
+
 mkdir -p "${BACKUP_DIR}"
 
 BACKUP_FILE="${BACKUP_DIR}/${DB_NAME}_${TIMESTAMP}.sql.gz"
@@ -21,7 +30,14 @@ BACKUP_FILE="${BACKUP_DIR}/${DB_NAME}_${TIMESTAMP}.sql.gz"
 echo "[$(date)] Starting backup of ${DB_NAME} on ${DB_HOST}:${DB_PORT}"
 
 # pg_dump with compression — mirrors Chatwoot backup approach
-PGPASSWORD="${POSTGRES_PASSWORD}" pg_dump     -h "${DB_HOST}"     -p "${DB_PORT}"     -U "${DB_USER}"     -d "${DB_NAME}"     --format=custom     --compress=9     | gzip > "${BACKUP_FILE}"
+PGPASSWORD="${DB_PASS}" pg_dump \
+    -h "${DB_HOST}" \
+    -p "${DB_PORT}" \
+    -U "${DB_USER}" \
+    -d "${DB_NAME}" \
+    --format=custom \
+    --compress=9 \
+    | gzip > "${BACKUP_FILE}"
 
 BACKUP_SIZE=$(du -h "${BACKUP_FILE}" | cut -f1)
 echo "[$(date)] Backup complete: ${BACKUP_FILE} (${BACKUP_SIZE})"

backend/scripts/migrate.sh

@@ -6,17 +6,16 @@
 set -e
 
 MIGRATIONS_DIR="./migrations"
-DB_HOST="${POSTGRES_HOST:-localhost}"
-DB_PORT="${POSTGRES_PORT:-5432}"
-DB_NAME="${POSTGRES_DATABASE:-gochat_dev}"
-DB_USER="${POSTGRES_USERNAME:-postgres}"
-DB_PASS="${POSTGRES_PASSWORD:-}"
-
-DSN="postgres://${DB_USER}:${DB_PASS}@${DB_HOST}:${DB_PORT}/${DB_NAME}?sslmode=disable"
+DSN="${GOCHAT_DATABASE_DSN:-postgres://postgres:postgres@localhost:5432/gochat_dev?sslmode=disable}"
 
 case "$1" in
   create)
-    echo "Creating database ${DB_NAME}..."
+    echo "Creating database from DSN..."
+    # Extract dbname from DSN for createdb
+    DB_NAME=$(echo "$DSN" | sed 's|.*/||; s|\?.*||')
+    DB_HOST=$(echo "$DSN" | sed 's|.*@||; s|:.*||')
+    DB_PORT=$(echo "$DSN" | sed 's|.*@.*:||; s|/.*||')
+    DB_USER=$(echo "$DSN" | sed 's|.*://||; s|:.*||')
     createdb -h "${DB_HOST}" -p "${DB_PORT}" -U "${DB_USER}" "${DB_NAME}" 2>/dev/null || echo "Database already exists"
     ;;
   up)

backend/scripts/seed.sh

@@ -43,8 +43,13 @@ if [[ "${1:-}" == "--clean" ]]; then
         exit 1
     fi
     log_warn "Cleaning all data before seeding..."
-    # Truncate tables in safe order (preserve migrations/schema)
-    psql_cmd="psql -h ${POSTGRES_HOST:-localhost} -p ${POSTGRES_PORT:-5432} -U ${POSTGRES_USER:-gochat} -d ${POSTGRES_DB:-gochat_dev}"
+    # Parse DSN for psql connection
+    DB_HOST=$(echo "$GOCHAT_DATABASE_DSN" | sed 's|.*@||; s|:.*||')
+    DB_PORT=$(echo "$GOCHAT_DATABASE_DSN" | sed 's|.*@.*:||; s|/.*||')
+    DB_USER=$(echo "$GOCHAT_DATABASE_DSN" | sed 's|.*://||; s|:.*||')
+    DB_PASS=$(echo "$GOCHAT_DATABASE_DSN" | sed 's|.*://[^:]*:||; s|@.*||')
+    DB_NAME=$(echo "$GOCHAT_DATABASE_DSN" | sed 's|.*/||; s|\?.*||')
+    psql_cmd="PGPASSWORD=${DB_PASS} psql -h ${DB_HOST} -p ${DB_PORT} -U ${DB_USER} -d ${DB_NAME}"
     $psql_cmd -c "
         TRUNCATE TABLE
             messages,