feat: add Cache TTL Override per account + bump VERSION to 0.1.83

- Account-level cache TTL override: rewrite Anthropic cache_creation
  token classification (5m↔1h) in streaming/non-streaming responses
- New DB field cache_ttl_overridden in usage_log for billing tracking
- Migration 055_add_cache_ttl_overridden
- Frontend: CacheTTL override toggle in account create/edit modals
- Ent schema regenerated for new usage_log fields

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/ent/usagelog_create.go

@@ -393,6 +393,20 @@ func (_c *UsageLogCreate) SetNillableImageSize(v *string) *UsageLogCreate {
 	return _c
 }
 
+// SetCacheTTLOverridden sets the "cache_ttl_overridden" field.
+func (_c *UsageLogCreate) SetCacheTTLOverridden(v bool) *UsageLogCreate {
+	_c.mutation.SetCacheTTLOverridden(v)
+	return _c
+}
+
+// SetNillableCacheTTLOverridden sets the "cache_ttl_overridden" field if the given value is not nil.
+func (_c *UsageLogCreate) SetNillableCacheTTLOverridden(v *bool) *UsageLogCreate {
+	if v != nil {
+		_c.SetCacheTTLOverridden(*v)
+	}
+	return _c
+}
+
 // SetCreatedAt sets the "created_at" field.
 func (_c *UsageLogCreate) SetCreatedAt(v time.Time) *UsageLogCreate {
 	_c.mutation.SetCreatedAt(v)
@@ -531,6 +545,10 @@ func (_c *UsageLogCreate) defaults() {
 		v := usagelog.DefaultImageCount
 		_c.mutation.SetImageCount(v)
 	}
+	if _, ok := _c.mutation.CacheTTLOverridden(); !ok {
+		v := usagelog.DefaultCacheTTLOverridden
+		_c.mutation.SetCacheTTLOverridden(v)
+	}
 	if _, ok := _c.mutation.CreatedAt(); !ok {
 		v := usagelog.DefaultCreatedAt()
 		_c.mutation.SetCreatedAt(v)
@@ -627,6 +645,9 @@ func (_c *UsageLogCreate) check() error {
 			return &ValidationError{Name: "image_size", err: fmt.Errorf(`ent: validator failed for field "UsageLog.image_size": %w`, err)}
 		}
 	}
+	if _, ok := _c.mutation.CacheTTLOverridden(); !ok {
+		return &ValidationError{Name: "cache_ttl_overridden", err: errors.New(`ent: missing required field "UsageLog.cache_ttl_overridden"`)}
+	}
 	if _, ok := _c.mutation.CreatedAt(); !ok {
 		return &ValidationError{Name: "created_at", err: errors.New(`ent: missing required field "UsageLog.created_at"`)}
 	}
@@ -762,6 +783,10 @@ func (_c *UsageLogCreate) createSpec() (*UsageLog, *sqlgraph.CreateSpec) {
 		_spec.SetField(usagelog.FieldImageSize, field.TypeString, value)
 		_node.ImageSize = &value
 	}
+	if value, ok := _c.mutation.CacheTTLOverridden(); ok {
+		_spec.SetField(usagelog.FieldCacheTTLOverridden, field.TypeBool, value)
+		_node.CacheTTLOverridden = value
+	}
 	if value, ok := _c.mutation.CreatedAt(); ok {
 		_spec.SetField(usagelog.FieldCreatedAt, field.TypeTime, value)
 		_node.CreatedAt = value
@@ -1407,6 +1432,18 @@ func (u *UsageLogUpsert) ClearImageSize() *UsageLogUpsert {
 	return u
 }
 
+// SetCacheTTLOverridden sets the "cache_ttl_overridden" field.
+func (u *UsageLogUpsert) SetCacheTTLOverridden(v bool) *UsageLogUpsert {
+	u.Set(usagelog.FieldCacheTTLOverridden, v)
+	return u
+}
+
+// UpdateCacheTTLOverridden sets the "cache_ttl_overridden" field to the value that was provided on create.
+func (u *UsageLogUpsert) UpdateCacheTTLOverridden() *UsageLogUpsert {
+	u.SetExcluded(usagelog.FieldCacheTTLOverridden)
+	return u
+}
+
 // UpdateNewValues updates the mutable fields using the new values that were set on create.
 // Using this option is equivalent to using:
 //
@@ -2040,6 +2077,20 @@ func (u *UsageLogUpsertOne) ClearImageSize() *UsageLogUpsertOne {
 	})
 }
 
+// SetCacheTTLOverridden sets the "cache_ttl_overridden" field.
+func (u *UsageLogUpsertOne) SetCacheTTLOverridden(v bool) *UsageLogUpsertOne {
+	return u.Update(func(s *UsageLogUpsert) {
+		s.SetCacheTTLOverridden(v)
+	})
+}
+
+// UpdateCacheTTLOverridden sets the "cache_ttl_overridden" field to the value that was provided on create.
+func (u *UsageLogUpsertOne) UpdateCacheTTLOverridden() *UsageLogUpsertOne {
+	return u.Update(func(s *UsageLogUpsert) {
+		s.UpdateCacheTTLOverridden()
+	})
+}
+
 // Exec executes the query.
 func (u *UsageLogUpsertOne) Exec(ctx context.Context) error {
 	if len(u.create.conflict) == 0 {
@@ -2839,6 +2890,20 @@ func (u *UsageLogUpsertBulk) ClearImageSize() *UsageLogUpsertBulk {
 	})
 }
 
+// SetCacheTTLOverridden sets the "cache_ttl_overridden" field.
+func (u *UsageLogUpsertBulk) SetCacheTTLOverridden(v bool) *UsageLogUpsertBulk {
+	return u.Update(func(s *UsageLogUpsert) {
+		s.SetCacheTTLOverridden(v)
+	})
+}
+
+// UpdateCacheTTLOverridden sets the "cache_ttl_overridden" field to the value that was provided on create.
+func (u *UsageLogUpsertBulk) UpdateCacheTTLOverridden() *UsageLogUpsertBulk {
+	return u.Update(func(s *UsageLogUpsert) {
+		s.UpdateCacheTTLOverridden()
+	})
+}
+
 // Exec executes the query.
 func (u *UsageLogUpsertBulk) Exec(ctx context.Context) error {
 	if u.create.err != nil {