Auto-walk: gate on fork/rest, slow cadence, credit DnD streak

Four fixes for the auto-walk loop that was re-clearing the same room
every 15 min while a fork was pending, ignoring the rest lockout, and
not counting expedition activity toward the daily streak:

- advanceOnceWithOpts / runAutopilotWalk now short-circuit to stopFork
  when NodeChoices has a pending fork. Stops phantom kills + duplicate
  loot drops + fork re-prompts on the same cleared room.
- fireExpeditionAutoRuns honors restingLockoutRemaining so the
  background ticker no longer walks through a long rest.
- autoRunCooldown 15m -> 2h, autoRunTickInterval 5m -> 15m. Auto-walk
  DMs are now a once-in-a-while ping, not a steady drip.
- markActedToday + HasActedToday recognise LastActionDate. Wired into
  !rest short/long, !expedition start/abandon, !extract, foreground
  !zone advance, and !zone go so DnD-side activity credits the streak
  even when the expedition ends before midnight.

(cherry picked from commit 9e27fd8257a4c92150ad584b393bf5a72270b82c)

internal/plugin/dnd_rest.go

@@ -114,6 +114,7 @@ func (p *AdventurePlugin) handleDnDShortRest(ctx MessageContext) error {
 	if err := SaveDnDCharacter(c); err != nil {
 		return p.SendDM(ctx.Sender, "Couldn't save rest state: "+err.Error())
 	}
+	markActedToday(ctx.Sender)
 
 	var msg string
 	if c.HPCurrent > before {
@@ -208,6 +209,7 @@ func (p *AdventurePlugin) handleDnDLongRest(ctx MessageContext) error {
 	if err := SaveDnDCharacter(c); err != nil {
 		return p.SendDM(ctx.Sender, "Couldn't save rest state: "+err.Error())
 	}
+	markActedToday(ctx.Sender)
 	_ = refreshAllResources(ctx.Sender)
 	// Phase 9: spell slots refresh on long rest.
 	_ = refreshSpellSlots(ctx.Sender)