Add automatic multi-format report generation and ZIP archiving

Implements automatic generation of JSON, HTML, and ZIP outputs after every scan,
with all files sharing the same timestamp for easy correlation.

Features:
- Automatic HTML report generation after every scan
- ZIP archive creation containing JSON, HTML, and all screenshots
- Unified timestamp across all outputs (JSON, HTML, ZIP, screenshots)
- Graceful error handling (scan continues if HTML/ZIP generation fails)
- Email-ready ZIP archives for easy sharing

Technical changes:
- Fixed timestamp mismatch between scan() and save_report()
- Added generate_outputs() method to SneakyScanner class
- scan() now returns (report, timestamp) tuple
- save_report() accepts timestamp parameter instead of generating new one
- main() updated to call generate_outputs() for all output formats
- Added zipfile import and HTMLReportGenerator import
- Dockerfile updated to copy templates/ directory

Output structure:
- scan_report_YYYYMMDD_HHMMSS.json (JSON report)
- scan_report_YYYYMMDD_HHMMSS.html (HTML report)
- scan_report_YYYYMMDD_HHMMSS.zip (archive with JSON, HTML, screenshots)
- scan_report_YYYYMMDD_HHMMSS_screenshots/ (screenshots directory)

Documentation updated:
- README.md: Updated Output Format, Features, Quick Start sections
- CLAUDE.md: Updated Core Components, Scan Workflow, Key Design Decisions

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

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

README.md

@@ -40,14 +40,17 @@ A dockerized network scanning tool that uses masscan for fast port discovery, nm
   - Browser reuse for optimal performance
 
 ### Reporting & Output
-- **Machine-readable JSON output** format for easy post-processing
-- **HTML report generation**:
-  - Comprehensive HTML reports with dark theme for easy reading
+- **Automatic multi-format output** after each scan:
+  - Machine-readable JSON reports for post-processing
+  - Human-readable HTML reports with dark theme
+  - ZIP archives containing all outputs for easy sharing
+- **HTML report features**:
+  - Comprehensive reports with dark theme for easy reading
   - Summary dashboard with scan statistics, drift alerts, and security warnings
   - Site-by-site breakdown with expandable service details
   - Visual badges for expected vs. unexpected services
   - SSL/TLS certificate details with expiration warnings
-  - One-click generation from JSON scan data
+  - Automatically generated after every scan
 - **Dockerized** for consistent execution environment and root privilege isolation
 - **Expected vs. Actual comparison** to identify infrastructure drift
 - Timestamped reports with complete scan duration metrics
@@ -82,7 +85,11 @@ docker-compose build
 docker-compose up
 ```
 
-3. Check results in the `output/` directory
+3. Check results in the `output/` directory:
+   - `scan_report_YYYYMMDD_HHMMSS.json` - JSON report
+   - `scan_report_YYYYMMDD_HHMMSS.html` - HTML report
+   - `scan_report_YYYYMMDD_HHMMSS.zip` - ZIP archive
+   - `scan_report_YYYYMMDD_HHMMSS_screenshots/` - Screenshots directory
 
 ## Scan Performance
 
@@ -133,7 +140,13 @@ See `configs/example-site.yaml` for a complete example.
 
 ## Output Format
 
-Scan results are saved as JSON files in the `output/` directory with timestamps. Screenshots are saved in a subdirectory with the same timestamp. The report includes the total scan duration (in seconds) covering all phases: ping scan, TCP/UDP port discovery, service detection, and screenshot capture.
+After each scan completes, SneakyScanner automatically generates three output formats:
+
+1. **JSON Report** (`scan_report_YYYYMMDD_HHMMSS.json`): Machine-readable scan data with all discovered services, ports, and SSL/TLS information
+2. **HTML Report** (`scan_report_YYYYMMDD_HHMMSS.html`): Human-readable report with dark theme, summary dashboard, and detailed service breakdown
+3. **ZIP Archive** (`scan_report_YYYYMMDD_HHMMSS.zip`): Contains JSON report, HTML report, and all screenshots for easy sharing and archival
+
+All files share the same timestamp for easy correlation. Screenshots are saved in a subdirectory (`scan_report_YYYYMMDD_HHMMSS_screenshots/`) and included in the ZIP archive. The report includes the total scan duration (in seconds) covering all phases: ping scan, TCP/UDP port discovery, service detection, screenshot capture, and report generation.
 
 ```json
 {
@@ -278,11 +291,15 @@ Screenshots are captured on a best-effort basis:
 
 ## HTML Report Generation
 
-SneakyScanner can generate comprehensive HTML reports from JSON scan data, providing an easy-to-read visual interface for analyzing scan results.
+SneakyScanner automatically generates comprehensive HTML reports after each scan, providing an easy-to-read visual interface for analyzing scan results.
 
-### Generating Reports
+### Automatic Generation
 
-After completing a scan, generate an HTML report from the JSON output:
+HTML reports are automatically created after every scan completes, along with JSON reports and ZIP archives. All three outputs share the same timestamp and are saved to the `output/` directory.
+
+### Manual Generation (Optional)
+
+You can also manually generate HTML reports from existing JSON scan data:
 
 ```bash
 # Generate HTML report (creates report in same directory as JSON)