Add unit tests

[msabramo]

Note that interface was renamed to networkInterface in the code, because there seemed to be complications arising from the fact that interface is a reserved word in JavaScript.

abramowi at Marcs-MacBook-Pro-3 in ~/Code/OpenSource/WireMCP (unit-tests)
$ npm run test:coverage

> wiremcp@1.0.0 test:coverage
> jest --coverage

 PASS  test/integration.test.js
  WireMCP Integration Tests
    Server initialization
      ○ skipped should register all expected tools
      ○ skipped should register all expected prompts
      ○ skipped should connect to transport
    Complex workflow scenarios
      ✓ should handle full packet capture and threat analysis workflow (3 ms)
      ✓ should handle network issues gracefully across tools (1 ms)
      ✓ should handle large data sets efficiently (27 ms)
    Error recovery and resilience
      ✓ should recover from tshark path detection failures (1 ms)
      ✓ should handle URLhaus API failures gracefully (1 ms)
      ✓ should handle errors gracefully
    Performance considerations
      ✓ should handle concurrent tool executions (5 ms)
      ✓ should handle memory efficiently with large outputs (21 ms)
    Security considerations
      ✓ should handle malicious input safely (3 ms)

 PASS  ./index.test.js
  WireMCP Server
    findTshark utility
      ✓ should find tshark using which command (1 ms)
      ✓ should fallback to common paths when which fails (1 ms)
      ✓ should throw error when tshark not found anywhere
    capture_packets tool
      ✓ should capture packets successfully (1 ms)
      ✓ should handle capture errors
      ✓ should trim packets when output is too large (34 ms)
    get_summary_stats tool
      ✓ should get protocol hierarchy statistics
    get_conversations tool
      ✓ should get TCP conversation statistics (1 ms)
    check_threats tool
      ✓ should check IPs against URLhaus blacklist
      ✓ should handle URLhaus API failure gracefully (1 ms)
    check_ip_threats tool
      ✓ should check single IP against URLhaus
      ✓ should report clean IP
    analyze_pcap tool
      ✓ should analyze PCAP file successfully (1 ms)
      ✓ should handle missing PCAP file
    extract_credentials tool
      ✓ should extract HTTP Basic Auth credentials (1 ms)
      ✓ should extract FTP credentials (1 ms)
      ✓ should extract Kerberos hashes
      ✓ should handle no credentials found (1 ms)
    Error handling
      ✓ should handle tshark execution errors
      ✓ should handle invalid JSON from tshark (1 ms)
    Default parameters
      ✓ should use default interface and duration

----------|---------|----------|---------|---------|------------------------------------------------------------
File      | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s                                          
----------|---------|----------|---------|---------|------------------------------------------------------------
All files |   80.07 |    51.12 |   68.08 |   83.75 |                                                            
 index.js |   80.07 |    51.12 |   68.08 |   83.75 | ...440,455-458,505-506,518,539,560,581,601,621,642,661-662 
----------|---------|----------|---------|---------|------------------------------------------------------------
Test Suites: 2 passed, 2 total
Tests:       3 skipped, 30 passed, 33 total
Snapshots:   0 total
Time:        0.759 s, estimated 1 s
Ran all test suites.