/context command: add --compact flag to show only token usage

Feature request: /context command — add --compact or --brief flag

Currently /context shows 4 sections:

1. Context Usage (token grid + breakdown)
2. MCP tools (full list of all available MCP tools)
3. Memory files
4. Skills (full list)

Sections 2-4 can be very long (30+ MCP tools, 17 skills) and require scrolling past them to see the context usage grid — which is the primary reason for running /context.

Requested behavior

• /context --compact (or /context -c) — show ONLY the Context Usage section (grid + token breakdown)
• /context (no flag) — current behavior unchanged

Alternative

Show MCP/Skills/Memory sections above the context grid so the grid is always visible at the bottom without scrolling.

Use case

During long sessions, I frequently check context usage to decide when to compact. Having to scroll past 50+ lines of MCP tools and skills every time adds friction.

Current output example

Context Usage
⛁ ⛁ ⛁ ⛁ ⛁ ⛁ ⛁ ⛁ ⛁ ⛁   claude-opus-4-6 · 117k/200k tokens (58%)
...token breakdown...

MCP tools · /mcp (loaded on-demand)
└ mcp__claude_ai_Fellow_ai__get_action_items
└ mcp__claude_ai_Fellow_ai__get_meeting_participants
└ ... (30+ more lines)

Memory files · /memory
└ .claude/CLAUDE.md
└ .claude/projects/.../MEMORY.md

Skills · /skills
└ colin-fix
└ oc-admin
└ ... (17 more lines)

The only section I need 90% of the time is the first one.