chore: consolidate env files and update gitignore

Removed .env and .env.backup from git tracking and consolidated configuration into .env.example. Updated .gitignore to robustly prevent accidental inclusion of sensitive files.

internal/models/registry.go

@@ -0,0 +1,58 @@
+package models
+
+type ModelRegistry struct {
+	Providers map[string]ProviderInfo `json:"-"`
+}
+
+type ProviderInfo struct {
+	ID     string                   `json:"id"`
+	Name   string                   `json:"name"`
+	Models map[string]ModelMetadata `json:"models"`
+}
+
+type ModelMetadata struct {
+	ID         string           `json:"id"`
+	Name       string           `json:"name"`
+	Cost       *ModelCost       `json:"cost,omitempty"`
+	Limit      *ModelLimit      `json:"limit,omitempty"`
+	Modalities *ModelModalities `json:"modalities,omitempty"`
+	ToolCall   *bool            `json:"tool_call,omitempty"`
+	Reasoning  *bool            `json:"reasoning,omitempty"`
+}
+
+type ModelCost struct {
+	Input      float64  `json:"input"`
+	Output     float64  `json:"output"`
+	CacheRead  *float64 `json:"cache_read,omitempty"`
+	CacheWrite *float64 `json:"cache_write,omitempty"`
+}
+
+type ModelLimit struct {
+	Context uint32 `json:"context"`
+	Output  uint32 `json:"output"`
+}
+
+type ModelModalities struct {
+	Input  []string `json:"input"`
+	Output []string `json:"output"`
+}
+
+func (r *ModelRegistry) FindModel(modelID string) *ModelMetadata {
+	// First try exact match in models map
+	for _, provider := range r.Providers {
+		if model, ok := provider.Models[modelID]; ok {
+			return &model
+		}
+	}
+
+	// Try searching by ID in metadata
+	for _, provider := range r.Providers {
+		for _, model := range provider.Models {
+			if model.ID == modelID {
+				return &model
+			}
+		}
+	}
+
+	return nil
+}