fix(security): implement all 15 security fixes from penetration test V1

Security audit (2026-03-31): 5 HIGH + 10 MEDIUM issues, all fixed.

HIGH:
- H1: JWT password_version mechanism (pwv in Claims, middleware verification,
  auto-increment on password change)
- H2: Docker saas port bound to 127.0.0.1
- H3: TOTP encryption key decoupled from JWT secret (production bailout)
- H4+H5: Tauri CSP hardened (removed unsafe-inline, restricted connect-src)

MEDIUM:
- M1: Persistent rate limiting (PostgreSQL rate_limit_events table)
- M2: Account lockout (5 failures -> 15min lock)
- M3: RFC 5322 email validation with regex
- M4: Device registration typed struct with length limits
- M5: Provider URL validation on create/update (SSRF prevention)
- M6: Legacy TOTP secret migration (fixed nonce -> random nonce)
- M7: Legacy frontend crypto migration (static salt -> random salt)
- M8+M9: Admin frontend: removed JS token storage, HttpOnly cookie only
- M10: Pipeline debug log sanitization (keys only, 100-char truncation)

Also: fixed CLAUDE.md Section 12 (was corrupted), added title.rs middleware
skeleton, fixed RegisterDeviceRequest visibility.

crates/zclaw-saas/src/models/account.rs

@@ -31,7 +31,7 @@ pub struct AccountAuthRow {
     pub llm_routing: String,
 }
 
-/// Login 一次性查询行（合并用户信息 + password_hash + totp_secret）
+/// Login 一次性查询行（合并用户信息 + password_hash + totp_secret + 安全字段）
 #[derive(Debug, FromRow)]
 pub struct AccountLoginRow {
     pub id: String,
@@ -45,6 +45,9 @@ pub struct AccountLoginRow {
     pub totp_secret: Option<String>,
     pub created_at: String,
     pub llm_routing: String,
+    pub password_version: i32,
+    pub failed_login_count: i32,
+    pub locked_until: Option<String>,
 }
 
 /// operation_logs 表行