Add digest as a real outcome: suppressed care nudges get resurfaced, not lost

Vikunja #281. The interruption policy promised four outcomes — deliver_now,
queue, digest, drop — but only three existed: a care candidate the restraint
gate suppressed for quiet hours / away / calendar-busy simply vanished in
loop.Tick's `continue`, with only the trace remembering why.

internal/morning turned out not to be the natural drain: it's a fixed
Item/FactKey checklist engine, not a generic message bundler, so gate-
suppressed nudge text has nowhere to plug into its evidence model. Built a
parallel (but small, reusing the outbox's shape) durable digest instead:

- internal/store: digest_entries table + EnqueueDigestEntry (dedupes by
  rule+body, mirroring the delivery outbox's bodyHash), PendingDigestEntries,
  ExpireStaleDigestEntries, DrainDigestEntries (mark, never delete — an
  audit trail of what she actually said).
- internal/loop: DigestEligible(severity, blockedBy) is the pure boundary —
  only genuine restraint blocks (quiet_hours/calendar_busy/presence) even
  qualify (cooldown/snooze are not "suppression"); within care, Sev2 (break)
  digests, Sev1 (water/meal — stale by the time anyone could resurface them)
  drops. High severity never digests; alarms bypass the gate and deliver
  unchanged, on purpose.
- cmd/mavend/tick.go: each tick scans ExplainTick's trace for eligible
  blocked candidates, enqueues them, sweeps stale entries (24h expiry — the
  care rules are daily-cadence, so anything older is describing a day
  that's over), and drains the bundle only once the suppression reason has
  actually cleared, capped at 3 spoken items plus a trailing count so a
  digest can't turn into the exact nagging it was built to avoid.

Tests: store-level round-trip/restart-survival/dedupe/expiry/drain, loop-
level severity-boundary unit tests, and tick-level integration tests for
the drain-only-when-clear and never-digest-high-severity behavior.

cmd/mavend/tick.go

@@ -180,6 +180,17 @@ func (t *tickLoop) tick(ctx context.Context, now time.Time) {
 	// (with dedup) avoids re-queueing the same rule after a flush.
 	t.maybeFlush(ctx, now, state)
 
+	// gate-suppressed digest (Vikunja #281): rules the restraint gate held
+	// back this tick (quiet hours / away / calendar-busy), not because they
+	// weren't due, but because it wasn't the moment. Some of those are worth
+	// resurfacing later instead of just being lost — loop.DigestEligible
+	// draws that line. This is a SEPARATE mechanism from the in-memory
+	// digestQ above: that one batches candidates the gate already ALLOWED to
+	// fire; this one durably holds candidates the gate BLOCKED.
+	t.enqueueSuppressedDigest(ctx, trace, state, now)
+	t.expireStaleDigest(ctx, now)
+	t.maybeDrainDigest(ctx, state, now)
+
 	// routines: operator-declared scheduled behaviors. fire the ones whose cron
 	// crossed since last fire, delivered through the normal routing (voice when
 	// present, away channels otherwise). bodies are literal operator text — not
@@ -342,6 +353,133 @@ func (t *tickLoop) flushDigest(ctx context.Context, now time.Time, state loop.St
 	t.digestQ = nil
 }
 
+// digestExpiry — how long a gate-suppressed care nudge stays worth
+// resurfacing. 24h: these are daily-cadence rules (water/meal/break run on
+// hour-scale cooldowns and re-derive from facts that reset every day), so a
+// digest entry that outlives one full day is describing a day that's already
+// over — "you skipped a break yesterday" said tomorrow evening is noise, not
+// news. Bounding at one day also means a digest can never silently span a
+// weekend of quiet hours into an unbounded backlog.
+const digestExpiry = 24 * time.Hour
+
+// maxDigestSpokenItems — the bundle read-out is capped so "batched, not
+// dropped" cannot regress into "she dumps twelve things on me the moment I
+// walk in" — a digest that nags in bulk is worse than the drops it replaced.
+// Anything beyond the cap is still marked drained (it did get its moment;
+// the cap limits WORDS, not whether it counted) and folded into a trailing
+// count instead of being spoken in full.
+const maxDigestSpokenItems = 3
+
+// enqueueSuppressedDigest scans this tick's trace for care candidates the
+// gate blocked for a genuine restraint reason and durably records the
+// digest-eligible ones (loop.DigestEligible). Phrasing happens once, here,
+// at enqueue time — not re-derived at drain time — the same way queueNudge
+// phrases once and caches, so a rule suppressed for hours isn't re-prompting
+// the LLM every tick it stays blocked (EnqueueDigestEntry's rule+body dedupe
+// makes repeat calls here harmless, but skipping the phrase call entirely
+// when a pending entry already exists avoids the LLM round-trip too).
+func (t *tickLoop) enqueueSuppressedDigest(ctx context.Context, trace *loop.TickTrace, state loop.State, now time.Time) {
+	if trace == nil {
+		return
+	}
+	for _, tr := range trace.RuleTraces {
+		if !tr.PredicateResult || tr.GateResult {
+			continue // didn't want to fire, or wasn't suppressed
+		}
+		if !loop.DigestEligible(tr.Severity, tr.GateBlockedBy) {
+			continue
+		}
+		rule := loop.Rule{Name: tr.RuleName, Severity: tr.Severity}
+		cand := loop.Candidate{Rule: rule, Severity: tr.Severity, State: state}
+		pn, err := t.phraser.PhraseNudge(ctx, cand)
+		if err != nil {
+			log.Printf("tick: phrase digest candidate %s: %v", tr.RuleName, err)
+			continue
+		}
+		expires := now.Add(digestExpiry)
+		if _, deduped, err := t.store.EnqueueDigestEntry(ctx, tr.RuleName, int(tr.Severity), pn.Body, now, expires); err != nil {
+			log.Printf("tick: enqueue digest entry %s: %v", tr.RuleName, err)
+		} else if deduped {
+			// same suppressed nudge already pending — nothing new to say.
+			continue
+		}
+	}
+}
+
+// expireStaleDigest sweeps entries past their expiry once per tick — cheap
+// bookkeeping, mirrors ReconcileStaleDeliveryAttempts's shape.
+func (t *tickLoop) expireStaleDigest(ctx context.Context, now time.Time) {
+	n, err := t.store.ExpireStaleDigestEntries(ctx, now)
+	if err != nil {
+		log.Printf("tick: expire stale digest entries: %v", err)
+		return
+	}
+	if n > 0 {
+		log.Printf("tick: expired %d stale digest entr(y/ies) unspoken", n)
+	}
+}
+
+// maybeDrainDigest speaks the pending digest bundle once the gate's
+// suppression reasons have actually cleared — quiet hours over, back from
+// away, out of the meeting. Draining while still suppressed would just be a
+// second way to nag through quiet hours; the bundle waits for the same "is
+// it allowed right now" condition a live nudge already waits for.
+func (t *tickLoop) maybeDrainDigest(ctx context.Context, state loop.State, now time.Time) {
+	if state.QuietHours || state.CalendarBusy || state.Presence == store.Away {
+		return
+	}
+	entries, err := t.store.PendingDigestEntries(ctx, now)
+	if err != nil {
+		log.Printf("tick: pending digest entries: %v", err)
+		return
+	}
+	if len(entries) == 0 {
+		return
+	}
+
+	spoken := entries
+	extra := 0
+	if len(spoken) > maxDigestSpokenItems {
+		spoken = entries[:maxDigestSpokenItems]
+		extra = len(entries) - maxDigestSpokenItems
+	}
+	var b strings.Builder
+	maxSev := 0
+	for i, e := range spoken {
+		if i > 0 {
+			b.WriteString(" · ")
+		}
+		b.WriteString(e.Body)
+		if e.Severity > maxSev {
+			maxSev = e.Severity
+		}
+	}
+	if extra > 0 {
+		fmt.Fprintf(&b, " · и ещё %d", extra)
+	}
+	body := b.String()
+	summary := fmt.Sprintf("%d отложенных уведомлений", len(entries))
+
+	cand := loop.Candidate{
+		Rule:     loop.Rule{Name: "digest", Severity: loop.Severity(maxSev)},
+		Severity: loop.Severity(maxSev),
+		State:    state,
+	}
+	pn := delivery.PhrasedNudge{Candidate: cand, Body: body, Summary: summary}
+	t.cachePhrase(pn)
+	if _, err := t.dispatcher.DispatchNudge(ctx, pn, now); err != nil {
+		log.Printf("tick: dispatch digest bundle: %v", err)
+		return // leave entries pending; retried next tick
+	}
+	ids := make([]int64, len(entries))
+	for i, e := range entries {
+		ids[i] = e.ID
+	}
+	if err := t.store.DrainDigestEntries(ctx, ids, now); err != nil {
+		log.Printf("tick: drain digest entries: %v", err)
+	}
+}
+
 // routinesFromConfig maps the config's routine blocks to the engine type.
 // Validation (cron parses, name/body present, severity defaulted) already ran
 // in config.Load, so this is a pure field copy.