feat: enhance DoH profile management and resolver policy in modules

- Added `DohResolverPolicy` schema to OpenAPI documentation, defining policies for domain resolution.
- Updated module handling to support multiple DoH profiles via `doh_profile_ids` and introduced `doh_resolver_policy` in the API.
- Refactored related functions to accommodate the new DoH profile structure, ensuring backward compatibility with existing `doh_profile_id`.
- Enhanced UI components to allow selection and management of DoH profiles and policies in the web interface.
- Updated database interactions to handle new fields and ensure proper data normalization.

internal/store/doh_module.go

@@ -0,0 +1,110 @@
+package store
+
+import "strings"
+
+const (
+	DohPolicyPrimaryOnly = "primary_only"
+	DohPolicyFailover    = "failover"
+	DohPolicyUnion       = "union"
+)
+
+// NormalizeDohResolverPolicy returns a supported resolver policy name.
+func NormalizeDohResolverPolicy(policy string) string {
+	switch strings.TrimSpace(policy) {
+	case DohPolicyFailover, DohPolicyUnion:
+		return strings.TrimSpace(policy)
+	default:
+		return DohPolicyPrimaryOnly
+	}
+}
+
+// NormalizeDohProfileIDList deduplicates profile ids preserving order.
+func NormalizeDohProfileIDList(ids []string) []string {
+	if len(ids) == 0 {
+		return nil
+	}
+	seen := make(map[string]struct{}, len(ids))
+	out := make([]string, 0, len(ids))
+	for _, id := range ids {
+		id = strings.TrimSpace(id)
+		if id == "" {
+			continue
+		}
+		if _, ok := seen[id]; ok {
+			continue
+		}
+		seen[id] = struct{}{}
+		out = append(out, id)
+	}
+	if len(out) == 0 {
+		return nil
+	}
+	return out
+}
+
+// EffectiveDohProfileIDs returns ordered DoH profile ids for a module.
+func (m *Module) EffectiveDohProfileIDs() []string {
+	if m == nil {
+		return nil
+	}
+	if ids := NormalizeDohProfileIDList(m.DohProfileIDs); len(ids) > 0 {
+		return ids
+	}
+	if m.DohProfileID != nil {
+		if id := strings.TrimSpace(*m.DohProfileID); id != "" {
+			return []string{id}
+		}
+	}
+	return nil
+}
+
+// SyncLegacyDohProfileID keeps deprecated doh_profile_id aligned with the first profile.
+func (m *Module) SyncLegacyDohProfileID() {
+	if m == nil {
+		return
+	}
+	ids := NormalizeDohProfileIDList(m.DohProfileIDs)
+	if len(ids) == 0 {
+		m.DohProfileID = nil
+		return
+	}
+	first := ids[0]
+	m.DohProfileID = &first
+}
+
+// NormalizeModuleDoh fills doh_profile_ids, policy and legacy id from module input.
+func NormalizeModuleDoh(m *Module) {
+	if m == nil {
+		return
+	}
+	ids := NormalizeDohProfileIDList(m.DohProfileIDs)
+	if len(ids) == 0 && m.DohProfileID != nil {
+		if id := strings.TrimSpace(*m.DohProfileID); id != "" {
+			ids = []string{id}
+		}
+	}
+	m.DohProfileIDs = ids
+	m.DohResolverPolicy = NormalizeDohResolverPolicy(m.DohResolverPolicy)
+	m.SyncLegacyDohProfileID()
+}
+
+// ApplyModuleDohPatch merges DoH-related fields from patch into mod.
+func ApplyModuleDohPatch(mod *Module, patch *ModulePatch) {
+	if mod == nil || patch == nil {
+		return
+	}
+	if patch.DohProfileIDs != nil {
+		mod.DohProfileIDs = NormalizeDohProfileIDList(*patch.DohProfileIDs)
+	} else if patch.DohProfileID != nil {
+		v := strings.TrimSpace(*patch.DohProfileID)
+		if v == "" {
+			mod.DohProfileIDs = nil
+		} else {
+			mod.DohProfileIDs = []string{v}
+		}
+	}
+	if patch.DohResolverPolicy != nil {
+		mod.DohResolverPolicy = NormalizeDohResolverPolicy(*patch.DohResolverPolicy)
+	}
+	mod.SyncLegacyDohProfileID()
+}