Summary

This PR tightens the desktop UI metrics shown around chat context and token usage. The main user-facing areas touched are the bottom status bar and the right-side Context overview panel.

Bottom status bar

• Adds a current-turn total token metric next to the existing cumulative session token metric. This uses a new turnTotalTokens state value so it reflects the total tokens reported for the current or most recent exchange, rather than reusing the existing completion-only turnTokens value used by the composer.
• Adds the active session turn count to the status bar. The value prefers the current topic metadata from the project tree and falls back to checkpoints/transcript user turns so it stays useful in both normal and browser-mock modes.
• Replaces long text labels for dense status metrics with compact Lucide icons plus tooltips. This keeps the bar readable while preserving explanations for cache hit rate, session tokens, turn tokens, turns, context usage, compaction threshold, cost, and balance.
• Fixes responsive hiding so hidden metrics remove the entire tooltip wrapper instead of leaving blank gaps or separator marks.

Context overview donut

• Fixes the donut fill so the ring endpoint is always based on current context usage (usedTokens / windowTokens) rather than provider/session totals. This prevents cases like 61k / 1000k = 6% visually rendering as an almost-full ring.
• Normalizes provider breakdown values when they exceed the current used context tokens, so Prompt/Completion/Reasoning/Other always sum back to the displayed used-token total.
• Treats reasoning tokens as a subset of completion tokens. The Context overview now displays Completion as non-reasoning completion, Reasoning separately, and Other as the remaining current context usage.

Tests

• Adds context-panel-breakdown.test.ts to lock the context donut math. The test covers reasoning not being double-counted and oversized provider breakdown values not filling the ring.
• Wires the new test into the desktop frontend test scripts.

Verification

• pnpm exec tsx src/__tests__/context-panel-breakdown.test.ts
• pnpm run typecheck
• pnpm run test:typecheck

Notes

• Untracked local .codex/ and designs/ directories were left out of this PR.