`bash lib/profile.sh current` is 12s+ — far too slow to call from the
statusline hook (runs on every keystroke). Add a one-line cache file at
`<repo>/.active-profile`, written by `cmd_apply` and `cmd_reset`. The
statusline reads the file directly with a single `head -n1`, no
sub-shell into `profile.sh`.
Behavior:
- `bash lib/profile.sh set <name>` (which ends in `cmd_apply`) and
`bash lib/profile.sh apply <name>` both write `<name>` to
`<repo>/.active-profile`.
- `bash lib/profile.sh reset` writes the literal `none`.
- Statusline inserts the cached profile name between the plan segment
and the context-bar segment, e.g.
`Opus 4.7 | claude (master) | Max | full | ████░░░░░░ 42% | 3m`.
- Missing or empty cache → statusline shows `?`.
Cache file is gitignored — it tracks runtime state, not source.
Co-Authored-By: Claude <noreply@anthropic.com>
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