Encounters track last_action_at (updated on attack and defend). If 30
seconds pass with no actions, combat fizzles out with a message to both
players and combat mode is popped. start_encounter initializes the
timestamp so fresh encounters don't immediately timeout.
Defenses now work outside combat mode with stamina cost, recovery lock
(based on timing_window_ms), and broadcast to nearby players. Lock
prevents spamming defenses — you commit to the move. Stamina deduction
moved from encounter.defend() to do_defend command layer. Defense
commands registered with mode="*" instead of "combat".
Attacker can change their move mid-telegraph or mid-window without
resetting the timer. Old move's stamina is refunded, new move charged.
Defender gets a fresh telegraph on switch. Feedback says "switch to"
instead of "use" when swapping attacks.
resolve() returns ResolveResult dataclass with attacker_msg, defender_msg,
damage, countered, and combat_ended fields. process_combat is now async
and sends messages to both participants on resolve. Counter, hit, and
slam messages give each player their own perspective on what happened.
