Unify Report Types for HTML Report Generation

[nirs]

This PR refactors the report types to enable generic HTML report generation. Previously, validate and test packages had their own Report types with separate Summary implementations, making it difficult to create a single HTML template.

Key Changes

Unified Summary Type (report.Summary)

• Add generic Summary type as map[SummaryKey]int in report package
• Each package defines its own keys:
  • validate.OK, validate.Stale, validate.Problem
  • test.Passed, test.Failed, test.Skipped, test.Canceled
• Add Summary.Equal() method for nil-safe pointer comparison
• Move Summary to report.Base so both report.Report and test.Report share it
• Consolidate Summary tests in report package, remove duplicates

Package-scoped Summary Keys

Keys are exported for external consumers to query reports without hardcoding strings:

if report.Summary.Get(validate.Problem) > 0 {
    // handle problems
}

Inside each package, the code reads like a struct with named fields:

report.Summary{OK: 23, Problem: 1}

Eliminate validate.Report

• Remove validate.Report struct - validate package now uses report.Report directly
• Keep package-specific helpers: addValidation(), hasIssues(), summaryString()

Simplify test.Report

• Remove Summary field from test.Report (gets it from embedded Base)
• Keep package-specific helpers: addTest(), summaryString()

Refactor YAML Report Writing

• Add report.WriteYAML(io.Writer, any) for generic YAML serialization
• Add command.OpenReport(format) for file management
• Separate concerns: command handles files, report handles serialization

Other

• Add .cursor/rules.md with project conventions for AI assistants

Result

With these changes, both validate and test commands share the same Summary type through report.Base. This is a prerequisite for creating a single HTML template that works with all command reports.

[parikshithb]

Looks great! Well structured, was easy to follow.