MCPProxyRepo: Add project_uuid filter to List and Count queries (before LIMIT/OFFSET)

Summary

MCPProxyRepo.List and MCPProxyRepo.Count in platform-api/src/internal/repository/mcp.go only scope by organization UUID. The projectId filter is currently applied after pagination in the handler, which causes MCP proxies to be dropped from later pages and renders the count/pagination incorrect.

Problem

• List query uses WHERE a.organization_uuid = ? only — no project_uuid predicate.
• Count query similarly omits project_uuid from its WHERE clause.
• As a result, filtering by project happens post-pagination, causing incorrect counts and incomplete pages.

Expected Fix

• Thread an optional projectUUID *string parameter into both MCPProxyRepo.List and MCPProxyRepo.Count.
• Add AND p.project_uuid = ? to both SQL queries when projectUUID is non-nil, before ORDER BY / LIMIT / OFFSET.
• Update parameter binding order in r.db.Query / r.db.QueryRow accordingly.
• Update the MCPProxyRepository interface in platform-api/src/internal/repository/interfaces.go to reflect the new signatures.
• Update callers (handler and service layers) to pass the project filter down to the repository.

References

• PR: https://github.com/wso2/api-platform/pull/1332
• Review comment: https://github.com/wso2/api-platform/pull/1332#discussion_r2909770625

/cc @RakhithaRR