feat: always-on context usage display with sub-1% precision

[thanhnnict]

Problem

Currently, the context usage indicator in Continue is only shown when:

• The conversation is pruned (context exceeded)
• OR context usage is >= 60%

This means users have no visibility into context consumption during normal usage. They only discover context limits when it is too late — after pruning has already occurred and information has been lost.

Solution

Make the context usage indicator always visible when there is conversation history, with enhanced precision and visual feedback.

Changes

ContextStatus.tsx

• Always visible when history.length > 0 (removed 60% threshold)
• Sub-1% precision: shows 0.3% instead of rounding to 0%
• Color-coded bar:
  • < 60%: muted (subtle, non-intrusive)
  • >= 60%: description (noticeable)
  • >= 80%: warning (attention needed)
  • pruned: error (action required)
• Percentage number displayed next to the bar
• Graceful handling: shows — before first message (when contextPercentage is undefined)

ResponseActions.tsx

• Always show Compact label on the last message
• Percentage prefix: 0.3% · Compact
• Hide prefix when no context data yet

Screenshots

Context usage at 4% — always visible, subtle when low
Context usage at 80%+ — warning color, clearly visible

Inspiration

This UX pattern is inspired by Kiro IDE, which always shows context usage to help users proactively manage their context budget.

Backward Compatibility

• No breaking changes
• No new dependencies
• Purely additive UI enhancement
• Existing behavior preserved when history.length === 0

[github-actions]

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[thanhnnict]