feat: add session persistence, state management commands, and --new-tab click (#184)

Rebased and fixed implementation of PR #184 features on current main:

Session persistence:
- --session-name flag and AGENT_BROWSER_SESSION_NAME env var auto-save/restore
  cookies and localStorage across browser restarts
- State files stored in ~/.agent-browser/sessions/ with owner-only permissions
- AES-256-GCM encryption via AGENT_BROWSER_ENCRYPTION_KEY env var
- Auto-expiration of old state files (AGENT_BROWSER_STATE_EXPIRE_DAYS, default 30)

State management commands:
- state list: list saved state files with metadata
- state show <file>: display state summary (cookies, origins, domains)
- state rename <old> <new>: rename state files
- state clear [name] [--all]: clear saved states
- state clean --older-than <days>: delete expired states

New --new-tab flag for click command:
- Opens link href in a new tab instead of navigating the current tab

Security hardening:
- Session name validation prevents path traversal (CLI + daemon)
- safeHeaderMerge prevents prototype pollution in header merging
- WebSocket stream server binds to 127.0.0.1 only
- State files written with 0o600 permissions

Fixes applied over the original PR:
- Use color.rs module instead of hardcoded ANSI escape codes
- Align CLI output field names with daemon response format
- Add CLI-level --session-name validation (not just daemon-side)
- Avoid adding "DOM" to tsconfig.json lib (use proper typing in evaluate)
- Keep version at 0.9.3 (matches current main)
- Centralize session name validation in daemon.ts helper
- Update all documentation (README, SKILL.md, docs site, --help output)

Co-authored-by: Chris Tate <chris@ctate.dev>

cli/src/connection.rs

@@ -219,6 +219,7 @@ pub fn ensure_daemon(
     state: Option<&str>,
     provider: Option<&str>,
     device: Option<&str>,
+    session_name: Option<&str>,
 ) -> Result<DaemonResult, String> {
     // Check if daemon is running AND responsive
     if is_daemon_running(session) && daemon_ready(session) {
@@ -359,6 +360,10 @@ pub fn ensure_daemon(
             cmd.env("AGENT_BROWSER_IOS_DEVICE", d);
         }
 
+        if let Some(sn) = session_name {
+            cmd.env("AGENT_BROWSER_SESSION_NAME", sn);
+        }
+
         // Create new process group and session to fully detach
         unsafe {
             cmd.pre_exec(|| {
@@ -438,6 +443,10 @@ pub fn ensure_daemon(
             cmd.env("AGENT_BROWSER_IOS_DEVICE", d);
         }
 
+        if let Some(sn) = session_name {
+            cmd.env("AGENT_BROWSER_SESSION_NAME", sn);
+        }
+
         // CREATE_NEW_PROCESS_GROUP | DETACHED_PROCESS
         const CREATE_NEW_PROCESS_GROUP: u32 = 0x00000200;
         const DETACHED_PROCESS: u32 = 0x00000008;