feat: she can suggest + switch modes (set_mode tool + mode awareness)

"She suggests, you confirm" — instead of brittle keyword→mode mapping, she's given
awareness of her modes + the ability to switch, and her judgment decides when to
offer (the model reads "should I drive to Cleveland?" vs "should I fold the river"
far better than a lexicon could).

- tools: set_mode(mode) — switches the session's mode; in _BASE (all modes).
- mind: a per-turn mode-menu note listing her modes + "offer a switch when the work
  clearly shifts; on his yes, call set_mode; don't nag."
- Sticky mode stays manual otherwise; Poker still auto-engages on session start.
- test: set_mode switches + rejects unknown. Suite 97 green, ruff clean.

Note: server-side switch takes effect next turn; the UI badge syncs on next mode
load (cosmetic lag).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

lyra/modes.py

@@ -42,7 +42,7 @@ _LOOKUPS = ("player_profile", "get_villain_file", "running_stats", "recent_sessi
 
 # Always-available core tools (her own agency: journaling/notes/starting a thought
 # thread, and capturing Brian's reaction when she raises one of her thoughts in chat).
-_BASE = ("journal_write", "note", "think_about", "thought_response")
+_BASE = ("journal_write", "note", "think_about", "thought_response", "set_mode")
 
 # The full live cash-game toolset (incl. Brian's mental-game rituals).
 _CASH_TOOLS = _BASE + _LOOKUPS + (