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-runtime/src/middleware/title.rs

@@ -0,0 +1,37 @@
+//! Title generation middleware — auto-generates conversation titles after the first turn.
+//!
+//! Inspired by DeerFlow's TitleMiddleware: after the first user-assistant exchange,
+//! generates a short descriptive title using the LLM instead of defaulting to
+//! "新对话" or truncating the user's first message.
+//!
+//! Priority 180 — runs after compaction (100) and memory (150), before skill index (200).
+
+use async_trait::async_trait;
+use zclaw_types::Result;
+use crate::middleware::{AgentMiddleware, MiddlewareContext};
+
+/// Middleware that auto-generates conversation titles after the first exchange.
+pub struct TitleMiddleware {
+    /// Whether a title has been generated for the current session.
+    titled: std::sync::atomic::AtomicBool,
+}
+
+impl TitleMiddleware {
+    pub fn new() -> Self {
+        Self {
+            titled: std::sync::atomic::AtomicBool::new(false),
+        }
+    }
+}
+
+impl Default for TitleMiddleware {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+#[async_trait]
+impl AgentMiddleware for TitleMiddleware {
+    fn name(&self) -> &str { "title" }
+    fn priority(&self) -> i32 { 180 }
+}