Improve MySQL JS fingerprint with native handshake parsing

[Mzack9999]

Summary

• Replace fingerprintx in FingerprintMySQL / IsMySQL with a native MySQL greeting parser (one dial).
• Expose handshake fields beyond version: protocol version, thread ID, capabilities, charset, status, salt, auth plugin (plus existing error packet debug).
• Keep version detection aligned with fingerprintx; cover with unit, client, and docker integration tests (MySQL 5.7/8.0/8.4, MariaDB 11.4).

Closes #4789

Summary by CodeRabbit

• New Features
  • Added richer MySQL service fingerprinting details (server/protocol version, capabilities/status, charset, authentication plugin, salt, and connection metadata).
  • Enhanced support for fingerprinting multiple MySQL and MariaDB versions.
• Bug Fixes
  • Improved MySQL detection and fingerprinting consistency by reusing a single connection attempt.
• Tests
  • Added extensive unit and client-harness tests for valid/invalid handshakes and error greetings.
  • Added an integration MySQL fingerprinting test case that runs when container tooling is available.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: 5823c200-7f1e-411c-9000-11174112b0d8

📥 Commits

Reviewing files that changed from the base of the PR and between c3a7fe0 and bc287ed.

📒 Files selected for processing (1)

• pkg/js/libs/mysql/fingerprint.go

🚧 Files skipped from review as they are similar to previous changes (1)

• pkg/js/libs/mysql/fingerprint.go

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Walkthrough

MySQL fingerprinting now parses and exposes handshake metadata, reuses memoized probes, preserves error details, and validates behavior across packet fixtures, client tests, and MySQL/MariaDB container versions.

Changes

MySQL fingerprint enrichment

Layer / File(s)	Summary
Packet parser and fingerprint contract pkg/js/libs/mysql/fingerprint.go	Adds MySQL greeting/error parsing, handshake enrichment, capability/status decoding, salt formatting, and JSON serialization.
Parser fixtures and compatibility validation pkg/js/libs/mysql/fingerprint_test.go	Tests valid handshakes, error packets, malformed inputs, helper functions, JSON output, and fingerprintx parity.
Client fingerprint integration pkg/js/libs/mysql/mysql.go	Uses memoized fingerprinting and exposes parsed handshake fields through MySQLInfo.
Client behavior tests pkg/js/libs/mysql/mysql_fingerprint_client_test.go	Validates handshake/error handling, memoized dialing, policy restrictions, rejection behavior, and version propagation.
JavaScript MySQL fingerprint integration internal/tests/integration/javascript_test.go	Runs the fingerprint template against MySQL and MariaDB container versions with readiness checks and combined failures.

Estimated code review effort: 4 (Complex) | ~45 minutes

Sequence Diagram(s)

sequenceDiagram
  participant Target
  participant IsMySQL
  participant FingerprintMySQL
  participant fingerprintConn
  Target->>fingerprintConn: MySQL greeting
  IsMySQL->>FingerprintMySQL: memoized fingerprint probe
  FingerprintMySQL->>fingerprintConn: parse greeting
  fingerprintConn-->>FingerprintMySQL: HandshakeInfo
  FingerprintMySQL-->>IsMySQL: MySQL availability and metadata

Loading

Poem

A rabbit hops through packets bright,
Finds salts and versions in the light.
MySQL speaks; the fields unfold,
MariaDB joins the testing hold.
“Hop, hop!” the fixtures cheer—
Fingerprints grow clearer here.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly describes the main change: native MySQL handshake parsing for JS fingerprinting.
Linked Issues check	✅ Passed	The PR adds native MySQL network-layer fingerprinting and exposes the handshake data requested in #4789.
Out of Scope Changes check	✅ Passed	The changes stay focused on MySQL fingerprinting and its tests, with no clear unrelated additions.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch 4789-mysql-fingerprint

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