[FEATURE] Show context usage percentage when exiting plan mode

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

When exiting plan mode, Claude offers the option to "clear context". However, there's no indication of how full the context actually is.

Sometimes the context is only 30% used and clearing it would waste valuable conversation history. Other times it's 85% full and clearing makes sense.

Without this information, I either:

• Always clear (losing useful context unnecessarily)
• Never clear (risking context overflow during implementation)
• Run /context manually before deciding (extra step)

Proposed Solution

When exiting plan mode, show context usage alongside the clear option:

Plan approved. Context: 42% used
[ ] Clear context before implementation
[Apply changes]

Or inline:

Context is 42% full. Clear before implementation? [Yes] [No, continue]

Alternative Solutions

• Manually running /context before exiting plan mode - works but adds friction
• Always clearing context - wastes conversation history when not needed
• Never clearing context - risks overflow on large implementations

Priority

Low - Quality of life improvement

Feature Category

User interface and experience

Use Case Example

1. User completes planning for a small feature
2. Plan mode shows: "Context: 25% used"
3. User sees context is mostly empty, skips clearing
4. User continues with full conversation history intact

vs.

1. User completes planning for a large refactor
2. Plan mode shows: "Context: 78% used"
3. User sees context is nearly full, chooses to clear
4. Implementation starts with fresh context

Additional Context

This enables informed decisions about context management without breaking the workflow.