[codex] Support Streamable HTTP MCP aliases

[ErlichLiu]

Summary

• normalize common Streamable HTTP MCP transport aliases (streamableHttp, streamable-http, streamable_http) to Proma's canonical http transport
• apply normalization when reading/saving workspace mcp.json, validating server configs, and building Agent SDK MCP server config
• update the Nowledge memory MCP setup prompt to use Proma's canonical http type
• add focused shared utility tests for MCP transport normalization and legacy type inference

Why

Proma already labels http as Streamable HTTP in the UI and passes type: 'http' to the Claude Agent SDK, which is the SDK's current Streamable HTTP discriminant. However, external MCP examples commonly use type: 'streamableHttp', and our own Nowledge prompt used that spelling. Those configs could fail validation or be skipped at runtime because Proma only accepted http and sse for URL-based MCP servers.

Validation

• bun test packages/shared/src/utils/mcp-transport.test.ts
• bun run --filter='@proma/shared' typecheck
• bun run --cwd apps/electron typecheck
• git diff --check