v4.0.2: Add Web UI authentication and optional HTTPS

- Add single-admin login with SQLite3 user storage
- First-run setup wizard for admin account creation
- Account management page for password changes
- Optional HTTPS with auto-generated self-signed certificates
- Configurable via STEGASOO_AUTH_ENABLED, STEGASOO_HTTPS_ENABLED env vars
- UI improvements: larger QR previews, consistent panel styling
- Update docker-compose.yml with auth config and persistent volumes
- Update all documentation for v4.0.2

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

API.md

@@ -1,4 +1,4 @@
-# Stegasoo REST API Documentation (v4.0.1)
+# Stegasoo REST API Documentation (v4.0.2)
 
 Complete REST API reference for Stegasoo steganography operations.
 
@@ -113,7 +113,7 @@ Check API status and configuration.
 
 ```json
 {
-  "version": "4.0.1",
+  "version": "4.0.2",
   "has_argon2": true,
   "has_qrcode_read": true,
   "has_dct": true,
@@ -462,7 +462,7 @@ X-Stegasoo-Capacity-Percent: 12.4
 X-Stegasoo-Embed-Mode: lsb
 X-Stegasoo-Channel-Mode: private
 X-Stegasoo-Channel-Fingerprint: ABCD-••••-...-3456
-X-Stegasoo-Version: 4.0.1
+X-Stegasoo-Version: 4.0.2
 
 <binary image data>
 ```