[Feature Request] `/context` command needs filtering and summarization for large MCP tool lists

Bug Description
Title: /context can't summarize or filter the MCP tool list

Type: Feature request

Summary
With many MCP servers connected (in my case, UnrealMCP exposes ~200 tools), the MCP section of /context enumerates every advertised tool name. I only care about the aggregate
token cost and which tools actually consumed context this session. Today there's no way to see either without scrolling the full list.

Current behavior

• /context lists every MCP tool name, even when ENABLE_TOOL_SEARCH=auto has deferred all their schemas.
• No flag, subcommand, or setting collapses the list or filters to invoked tools.
• /cost shows total spend but no per-tool breakdown.

Requested behavior (any of these would help)

1. A collapsed "MCP tools: N advertised, X tokens" line, with an opt-in expand.
2. A filter showing only tools whose schemas have been loaded via ToolSearch or that have been invoked this session.
3. A separate subcommand (e.g. /context mcp) for the detailed view.

Why it matters
When triaging context pressure mid-session, the MCP block is the noisiest part of /context but often the least actionable — the names themselves are cheap; what I actually want
to know is which schemas/results are sitting in the transcript.

Environment Info

• Platform: win32
• Terminal: windows-terminal
• Version: 2.1.113
• Feedback ID: 4073c7e7-f984-44d7-8224-51aba42ac85a