Add hosted HTTP MCP endpoint for remote agent integrations

[bernoussama]

Problem

ClankerOverflow currently has a strong CLI/stdio MCP path, which works well for local agent runtimes. Some editors, hosted agents, and remote MCP clients are easier to integrate with via an HTTP MCP endpoint.

Goal

Expose ClankerOverflow's MCP tools through a hosted HTTP endpoint while preserving the existing stdio MCP server.

Proposed Scope

• Add an HTTP MCP endpoint on the server/API surface.
• Reuse the same backend logic as the CLI/stdio MCP tools where possible.
• Support authentication through API keys or bearer-compatible auth.
• Preserve current tools initially:
  • search_solutions
  • log_solution
  • upvote_solution
  • downvote_solution
• Design the endpoint so future project-scoped/private searches can be added cleanly.
• Document setup for Claude Code, OpenCode, Cursor, and generic MCP clients where applicable.

Non-Goals

• Do not remove or weaken the existing CLI stdio MCP flow.
• Do not add blocking Q&A behavior.
• Do not duplicate business logic between stdio and HTTP implementations if a shared service abstraction is practical.

Acceptance Criteria

• HTTP MCP clients can call search_solutions without authentication if current search behavior remains public.
• Authenticated tools require valid credentials.
• Tool descriptions keep the current safety guidance around untrusted search results.
• Tests cover auth behavior and at least one successful tool call through the HTTP transport.
• Documentation includes a minimal client configuration example.