feat: surface bulk-suppressed ESLint violations as configurable diagnostics

[wagenet]

Summary

• Adds eslint.bulkSuppression setting (disabled by default — no behavior change for existing users)
• When enabled, violations moved to suppressedMessages by ESLint's bulk suppression API (kind === "file") are emitted as VS Code diagnostics at a configurable severity (default: info)
• Respects rulesCustomizations — rules set to off are still suppressed
• Requires ESLint ≥ the version that merged applySuppressions constructor support (eslint/eslint#20565)

New setting

"eslint.bulkSuppression": {
  "enable": true,          // false by default
  "severity": "hint",      // "error" | "warn" | "info" | "hint", defaults to "info"
  "suppressionsLocation": "path/to/eslint-suppressions.json" // optional
}

Test plan

• With enable: false (default), no change in behavior
• With enable: true, open a file with a bulk-suppressed violation — it appears at the configured severity
• The same violation does not appear in messages (ESLint moved it to suppressedMessages)
• A rule customized to off via rulesCustomizations does not produce a bulk diagnostic
• suppressionsLocation correctly overrides the default file path when set

🤖 Generated with Claude Code

[wagenet]

@microsoft-github-policy-service agree company="Optro"