[FEATURE]: Session context usage (similar to /context in Claude)

Summary

Implement a TUI dialog to visualize current session context window usage, similar to Claude's `/context` command. This involves creating a new server endpoint to expose session data and developing a frontend component to display this information effectively, helping users optimize context consumption.

Skills Required

TypeScriptTUI Development (e.g., with Ink, blessed, or a similar library)API DesignState Management

Files Likely Touched

packages/opencode/src/acp/session.ts
src/client/components/dialogs/ContextUsageDialog.tsx
src/client/services/sessionService.ts
src/client/commands/sessionCommands.ts

Labels

opentuidiscussion