Phase 4 (Performance) + Phase 6 (Infrastructure) completion

Phase 4 — Performance:
- F1: SSH DialPool with key-by-host pooling and 5min idle TTL
- F2: In-memory entity lookup cache (TTL 60s, HTTP resolveEntityID)
- F3: Trigram GIN indexes on entities.slug and entities.name (migration 031)
- F4: Partial index on executions(classification_id) for auto-act (migration 032)
- Added missing RunOutput and RunStreaming in actuator/ (E3 gap fill)

Phase 6 — Infrastructure:
- H1: Infisical image pinned to v0.99.1
- H2: execworker daemon — polls pending executions with per-execution
  advisory locks, recovers orphaned running executions, wired as
  docker-compose service
- H3: splitSQL hardened with block comment and string-literal support,
  6 new edge-case tests (11 total)
- H4: Scheduler acquires pg_try_advisory_lock(0x01c05e6) at startup

internal/db/entity_cache.go

@@ -0,0 +1,61 @@
+package db
+
+import (
+	"sync"
+	"time"
+)
+
+type entityCacheEntry struct {
+	slug  string
+	id    string
+	attrs string
+	exp   time.Time
+}
+
+type EntityCache struct {
+	mu   sync.RWMutex
+	m    map[string]entityCacheEntry
+	ttl  time.Duration
+}
+
+func NewEntityCache(ttl time.Duration) *EntityCache {
+	return &EntityCache{
+		m:   make(map[string]entityCacheEntry),
+		ttl: ttl,
+	}
+}
+
+func (c *EntityCache) GetSlug(id string) (string, bool) {
+	c.mu.RLock()
+	e, ok := c.m[id]
+	c.mu.RUnlock()
+	if !ok || time.Now().After(e.exp) {
+		return "", false
+	}
+	return e.slug, true
+}
+
+func (c *EntityCache) GetID(slug string) (string, bool) {
+	c.mu.RLock()
+	e, ok := c.m[slug]
+	c.mu.RUnlock()
+	if !ok || time.Now().After(e.exp) {
+		return "", false
+	}
+	return e.id, true
+}
+
+func (c *EntityCache) Set(slug, id, attrs string) {
+	exp := time.Now().Add(c.ttl)
+	c.mu.Lock()
+	c.m[slug] = entityCacheEntry{slug: slug, id: id, attrs: attrs, exp: exp}
+	c.m[id] = entityCacheEntry{slug: slug, id: id, attrs: attrs, exp: exp}
+	c.mu.Unlock()
+}
+
+func (c *EntityCache) Invalidate(slug, id string) {
+	c.mu.Lock()
+	delete(c.m, slug)
+	delete(c.m, id)
+	c.mu.Unlock()
+}