[task] Add required 'url' field to HTTP MCP tool schema

[github-actions]

Objective

Make the url field required in the MCP config schema for HTTP MCP tools to provide early validation feedback.

Context

This addresses Issue #2 from discussion #2969. Currently, the MCP config schema doesn't enforce the url field as required via JSON Schema, but the compiler enforces it at runtime in pkg/workflow/mcp-config.go:827. Users don't get IDE validation or early warning when url is missing.

Approach

1. Open pkg/parser/schemas/mcp_config_schema.json
2. Locate the http_mcp_tool definition
3. Add a conditional required array that enforces url when type is http
4. Follow the existing pattern used in MCP schemas (which are noted as "gold standard")

Files to Modify

• pkg/parser/schemas/mcp_config_schema.json - Add conditional requirement for url field in HTTP tools

Acceptance Criteria

• Schema validation fails when HTTP MCP tool lacks url field
• Schema validation passes when url is provided for HTTP tools
• Non-HTTP MCP tools are unaffected
• IDE validation provides early feedback
• Run make build and make test successfully
  Related to [Schema Consistency] 🔍 Schema Consistency Check - Required Fields & Error Documentation Gap (Nov 2, 2025) #2969

AI generated by Plan Command for discussion #2969