Add complete SchemaValidationFailure context to all parameter errors

[mjbonifacio]

What Changed

Adds full OpenAPI KeywordLocation paths and ReferenceSchema context to all parameter validation errors (path, query, header, cookie parameters). Uses the centralized JSON Pointer helpers from PR #2.

Why

Before this change, parameter validation errors had incomplete context:

• Missing ReferenceSchema field (couldn't see the schema that was violated)
• Missing or incomplete KeywordLocation (hard to locate the exact schema rule)
• Inconsistent patterns across different parameter types

Now all parameter errors include:

• Full OpenAPI path in KeywordLocation: e.g., /paths/~1users~1{id}/get/parameters/id/schema/minimum
• Rendered schema in ReferenceSchema: The actual schema definition as JSON string
• Consistent structure: All 4 parameter types follow the same pattern

This makes debugging much easier - you can see exactly which schema rule was violated and where it's defined in your OpenAPI spec.

Pattern Applied

Each parameter validation function now:

1. Renders the schema once (at the start of validation)
2. Passes renderedSchema to error functions (avoid re-rendering on each error)
3. Uses helper functions for KeywordLocation construction

Example (Path parameter validation):

// Render schema once for all errors
renderedSchema, _ := json.Marshal(param.Schema.Schema().RenderInline())

// Pass to error function
err := errors.IncorrectPathParamNumber(
    pathTemplate, operation, param.Name, 
    renderedSchema,  // ← New: for ReferenceSchema field
    value,
)

SchemaValidationFailure Changes

Path Parameter Validation

Error Type	Before	After	Changes
All path param errors (35 functions)	⚠️ Missing ReferenceSchema	✅ Has ReferenceSchema + full KeywordLocation	Added schema context and OpenAPI paths using helpers

Query Parameter Validation

Error Type	Before	After	Changes
All query param errors	⚠️ Missing ReferenceSchema	✅ Has ReferenceSchema + full KeywordLocation	Added schema context and OpenAPI paths using helpers
Missing required query param	❌ No SchemaValidationFailure	✅ Has SchemaValidationFailure	Added - this IS a schema constraint violation (required: true)

Header Parameter Validation

Error Type	Before	After	Changes
All header param errors	⚠️ Missing ReferenceSchema	✅ Has ReferenceSchema + full KeywordLocation	Added schema context and OpenAPI paths using helpers

Cookie Parameter Validation

Error Type	Before	After	Changes
All cookie param errors	⚠️ Missing ReferenceSchema	✅ Has ReferenceSchema + full KeywordLocation	Added schema context and OpenAPI paths using helpers

Dependency Note

⚠️ Depends on PR #1 and PR #2 - Review those first for context on SchemaValidationFailure usage and helper functions.

Commits (4)

1. Path parameters: render schema once, pass to error functions
2. Query parameters: add full OpenAPI context + missing required param fix
3. Header parameters: add full OpenAPI context
4. Cookie parameters: add full OpenAPI context