Surface context window usage in the UI

[juliusmarminge]

Summary

• Adds provider normalization for token usage snapshots from Codex and Claude runtime events.
• Projects token usage and compaction state into orchestration thread activities.
• Renders a compact context window meter in the chat composer area.
• Displays context compaction markers as centered timeline chips.
• Adds coverage for adapter normalization, orchestration ingestion, and UI rendering behavior.

Testing

• Not run in this pass.
• Added/updated tests for ClaudeAdapter, CodexAdapter, ProviderRuntimeIngestion, contextWindow, MessagesTimeline, and session logic.
• Repository task requirements still call for bun fmt, bun lint, bun typecheck, and bun run test before merge.

Note

Surface context window usage in the chat UI with a token meter

• Adds a ContextWindowMeter component to the chat composer bar that shows a circular SVG progress arc with used/remaining tokens and a popover with full details.
• Normalizes token usage events from both Claude and Codex adapters into a typed ThreadTokenUsageSnapshot contract, emitting thread.token-usage.updated provider runtime events at task progress and turn completion.
• Maps thread.token-usage.updated and thread.state.changed (state compacted) runtime events to new context-window.updated and context-compaction thread activities in ProviderRuntimeIngestion.
• Adds deriveLatestContextWindowSnapshot in contextWindow.ts to scan activities backwards for the latest usage snapshot, and formatContextWindowTokens for compact k/m display.
• context-window.updated activities are excluded from the work log; context-compaction entries remain visible with their label.
• Behavioral Change: ThreadTokenUsageUpdatedPayload now validates usage against a strict ThreadTokenUsageSnapshot schema — events that don't conform will fail decoding.

^{Macroscope summarized 4747000.}

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Note

Medium Risk
Introduces a new validated ThreadTokenUsageSnapshot schema and changes thread.token-usage.updated payload decoding/normalization; any producers sending unstructured usage data may now fail validation or be dropped. Also adds new activity kinds that affect timeline/work-log rendering, so regressions are possible if consumers assume the previous activity set.

Overview
Projects provider runtime signals into new thread activities: thread.token-usage.updated becomes context-window.updated (with a structured ThreadTokenUsageSnapshot payload) and thread.state.changed with state: "compacted" becomes context-compaction.

Updates Claude and Codex adapters to emit/unwrap normalized token-usage snapshots (handling multiple payload shapes and deriving Claude context-window size from modelUsage), and updates the contracts schema so thread.token-usage.updated is no longer Schema.Unknown.

Adds a compact context window meter (ContextWindowMeter) to ChatView driven by the latest context-window.updated activity, plus UI/session-logic tweaks so context-window updates are excluded from the work log while compaction entries remain visible, with new test coverage across adapters, ingestion, and UI helpers.

^{Written by Cursor Bugbot for commit 4747000. This will update automatically on new commits. Configure here.}

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