Judge a send by when a fault began, not when it was last raised (hq issue 348)

On 2026-10-09 the control node's resolver refused from 10:57:57 UTC. A
node-engine restarted by the 10:59:34 send said its names undecided, that
statement cleared the network condition, the next look raised it again
after the send, and the gate put back two builds for a fault older than
them.

- A condition keeps First across a reopening; the gate reads Began.
- An undecided network statement (unknown, starting) clears nothing.
- D10 counts what a release's tier names as rolling, so a walked
  node-engine is not core-behind on its own first machine.
- D2 raises a resolver that refuses every try at once: a refusal is an
  answer, not a loaded resolver (issue 277).

internal/conditions/store.go

@@ -77,8 +77,10 @@ type Keeper struct {
 }
 
 type clearing struct {
-	at       time.Time
-	count    int
+	at    time.Time
+	count int
+	// began is when the fault that cleared began, so its reopening keeps it (Condition.Began).
+	began    time.Time
 	silenced *Silence
 	// tried is what healers tried before it cleared: a reopening is the same fault, and what was
 	// tried on it is still what was tried.
@@ -120,8 +122,8 @@ func NewKeeper(ctx context.Context, o Options) *Keeper {
 		if recent, err := k.history.Since(ctx, k.now().Add(-ReopenWithin)); err == nil {
 			for _, e := range recent {
 				if e.Change == ChangeCleared {
-					k.cleared[e.Key] = clearing{at: e.At, count: e.Condition.Count, silenced: e.Condition.Silenced,
-						tried: e.Condition.Tried}
+					k.cleared[e.Key] = clearing{at: e.At, count: e.Condition.Count, began: e.Condition.Began(),
+						silenced: e.Condition.Silenced, tried: e.Condition.Tried}
 				}
 			}
 		} else {
@@ -197,6 +199,9 @@ func (k *Keeper) Observe(ctx context.Context, o Observation) (Condition, error)
 			k.mu.Lock()
 			if before, ok := k.cleared[key]; ok && now.Sub(before.at) <= ReopenWithin {
 				c.Count, change = before.count+1, ChangeReopened
+				if !before.began.IsZero() && before.began.Before(now) {
+					c.First = before.began
+				}
 				// A silence a person gave the condition before it cleared still holds: they said
 				// they knew, and the same fault again ten minutes later is what they knew about.
 				if before.silenced != nil && now.Before(before.silenced.Until) {
@@ -313,7 +318,7 @@ func (k *Keeper) ClearSaying(ctx context.Context, key, why, resolved string) (bo
 		}
 		now := k.now().UTC()
 		k.mu.Lock()
-		k.cleared[key] = clearing{at: now, count: c.Count, silenced: c.Silenced, tried: c.Tried}
+		k.cleared[key] = clearing{at: now, count: c.Count, began: c.Began(), silenced: c.Silenced, tried: c.Tried}
 		k.mu.Unlock()
 		k.tell(Event{Condition: c, At: now, Change: ChangeCleared, Why: why, Cleared: &now})
 		return true, nil