feat: config.yaml only, OpenRouter free models, remove runtime.json config

- Move all config (auto rules, keys) from runtime.json to config.yaml
- Store now only holds runtime sources (WebUI-created)
- Add OpenRouter free models to config.yaml
- One-time migration from legacy runtime.json on startup
- Fix gateway tests for new config structure
- Update core.go with migrateFromRuntime, saveConfig, seedKeys/seedAuto
- Remove SaveKey/KeyByValue/AutoRules from Store
- Add Config.Save() with YAML marshaling
- Update WebUI admin keys visibility (show all keys including admin)
- Bump binary to 11MB with luajit

internal/provider/registry.go

@@ -14,12 +14,12 @@ import (
 type Registry struct {
 	mu        sync.RWMutex
 	providers []*Provider
-	byModel   map[string]*Provider // modelID -> provider
-	defaultM  string               // default model id ("" means AUTO)
+	byModel   map[string][]*Provider // modelID -> providers (one per source)
+	defaultM  string                 // default model id ("" means AUTO)
 }
 
 func NewRegistry(providers []*Provider, defaultModel string) *Registry {
-	r := &Registry{byModel: map[string]*Provider{}, defaultM: defaultModel}
+	r := &Registry{byModel: map[string][]*Provider{}, defaultM: defaultModel}
 	r.set(providers)
 	return r
 }
@@ -33,12 +33,14 @@ func (r *Registry) Replace(providers []*Provider) {
 
 func (r *Registry) set(providers []*Provider) {
 	r.providers = providers
-	r.byModel = map[string]*Provider{}
+	m := map[string][]*Provider{}
 	for _, p := range providers {
-		for _, m := range p.Models() {
-			r.byModel[strings.ToLower(m)] = p
+		for _, model := range p.Models() {
+			key := strings.ToLower(model)
+			m[key] = append(m[key], p)
 		}
 	}
+	r.byModel = m
 }
 
 func (r *Registry) Providers() []*Provider {
@@ -102,10 +104,11 @@ func (r *Registry) Resolve(model string) []*Provider {
 	if p := r.ResolvePinned(model); p != nil {
 		return []*Provider{p}
 	}
-	// explicit model
-	if p, ok := r.byModel[strings.ToLower(model)]; ok {
-		// switch to the owning source but pin the model via request
-		return []*Provider{p}
+	// explicit model — may be served by multiple sources
+	if ps, ok := r.byModel[strings.ToLower(model)]; ok {
+		out := make([]*Provider, len(ps))
+		copy(out, ps)
+		return out
 	}
 	return nil
 }
@@ -151,18 +154,20 @@ func (r *Registry) ResolvePinned(model string) *Provider {
 }
 
 // ProviderForModel returns the provider owning the model id (nil if unknown).
+// When the same model exists on multiple sources, returns the first (source
+// config order). Callers that need a specific source use ProviderForSlot.
 func (r *Registry) ProviderForModel(model string) *Provider {
 	r.mu.RLock()
 	defer r.mu.RUnlock()
-	p, ok := r.byModel[strings.ToLower(strings.TrimSpace(model))]
-	if !ok {
+	ps, ok := r.byModel[strings.ToLower(strings.TrimSpace(model))]
+	if !ok || len(ps) == 0 {
 		return nil
 	}
-	return p
+	return ps[0]
 }
 
 // ProviderForSlot returns the provider for a (model, source) slot. When
-// source is empty it behaves like ProviderForModel (owner of the model id);
+// source is empty it behaves like ProviderForModel (first owner of the model id);
 // when source is set it returns only that exact source (nil if the source
 // does not serve the model).
 func (r *Registry) ProviderForSlot(model, source string) *Provider {
@@ -171,11 +176,11 @@ func (r *Registry) ProviderForSlot(model, source string) *Provider {
 	r.mu.RLock()
 	defer r.mu.RUnlock()
 	if source == "" {
-		p, ok := r.byModel[model]
-		if !ok {
+		ps, ok := r.byModel[model]
+		if !ok || len(ps) == 0 {
 			return nil
 		}
-		return p
+		return ps[0]
 	}
 	for _, p := range r.providers {
 		if !strings.EqualFold(p.Name(), source) {