[task] Fix container pattern regex in mcp_config_schema.json to allow colons

[github-actions]

Objective

Fix the container field regex pattern in mcp_config_schema.json to allow colons, matching the pattern used in other schemas.

Context

Related to discussion #2361 - Schema Consistency Check identified that the container field has DIFFERENT regex patterns across schemas. The MCP config schema currently REJECTS valid container images like registry:5000/myimage while other schemas accept them.

Problem

• mcp_config_schema.json: ^[a-zA-Z0-9][a-zA-Z0-9/_.-]*$ ❌ (NO colon)
• included_file_schema.json: ^[a-zA-Z0-9][a-zA-Z0-9/:_.-]*$ ✅ (colon allowed)
• main_workflow_schema.json: ^[a-zA-Z0-9][a-zA-Z0-9/:_.-]*$ ✅ (colon allowed)

Approach

In pkg/parser/schemas/mcp_config_schema.json line 24, update the container pattern:

• Change: ^[a-zA-Z0-9][a-zA-Z0-9/_.-]*$
• To: ^[a-zA-Z0-9][a-zA-Z0-9/:_.-]*$

Files to Modify

• pkg/parser/schemas/mcp_config_schema.json (line 24)

Acceptance Criteria

• Container pattern in mcp_config_schema.json matches the pattern in included_file_schema.json and main_workflow_schema.json
• Pattern allows colon character for registry ports (e.g., registry:5000/myimage)
• Run make build successfully (schemas are embedded, rebuild required)
• Run make test to ensure no regressions

AI generated by Plan Command for discussion #2361