v0.3.0 — context moves to the status line

Context-window usage moves out of a second menu bar widget and into Claude Code's status line (e.g. Opus 4.8 · 11% · 113K/1M).

Because each terminal pane renders its own status line, it always shows the session you're looking at — fixing the wrong-session mismatch seen in multi-pane setups (tmux, cmux). The window size (200K/1M) and token counts now come straight from Claude Code's context_window payload, so there's no transcript parsing or limit guessing.

Removed: the context menu bar widget and all active-session tracking it required (the --hook-relay hook, transcript parsing, the 200K/1M detection ladder, tty-atime focus). The menu bar now shows usage only; existing --hook-relay hooks are cleared from ~/.claude/settings.json.