Add comprehensive godoc documentation to all exported symbols

- Document all exported types, functions, methods, and constants across 52 files
- Add package-level doc comments to client, models, utils, and ynison packages
- Document HTTP method and endpoint path for each API client method
- Document model struct fields and DeJSON/DeList/ToJSON/ToMap methods
- Fix duplicate package doc comment in internal/models/base.go

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

internal/models/settings.go

@@ -1,17 +1,18 @@
+// Package models provides data models for the Yandex Music API.
 package models
 
 import (
 	"encoding/json"
 )
 
-// Experiments represents experiments
+// Experiments represents experiments from the Yandex Music API.
 type Experiments struct {
 	BaseModel
 	Experiments []ExperimentDetail `json:"experiments"`
 	Total       int                `json:"total"`
 }
 
-// DeJSON deserializes Experiments from JSON
+// DeJSON deserializes Experiments from JSON data.
 func (e *Experiments) DeJSON(data []byte, client ClientInterface) (Model, error) {
 	var raw map[string]json.RawMessage
 	if err := json.Unmarshal(data, &raw); err != nil {
@@ -32,7 +33,7 @@ func (e *Experiments) DeJSON(data []byte, client ClientInterface) (Model, error)
 	return experiments, nil
 }
 
-// DeList deserializes a list of Experiments
+// DeList deserializes a list of Experiments from JSON data.
 func (e *Experiments) DeList(data []byte, client ClientInterface) ([]Model, error) {
 	var rawList []json.RawMessage
 	if err := json.Unmarshal(data, &rawList); err != nil {
@@ -50,7 +51,7 @@ func (e *Experiments) DeList(data []byte, client ClientInterface) ([]Model, erro
 	return result, nil
 }
 
-// ExperimentDetail represents experiment details
+// ExperimentDetail represents experiment details.
 type ExperimentDetail struct {
 	BaseModel
 	ID          string `json:"id"`
@@ -62,7 +63,7 @@ type ExperimentDetail struct {
 	EndDate     string `json:"end_date"`
 }
 
-// DeJSON deserializes ExperimentDetail from JSON
+// DeJSON deserializes ExperimentDetail from JSON data.
 func (e *ExperimentDetail) DeJSON(data []byte, client ClientInterface) (Model, error) {
 	var raw map[string]json.RawMessage
 	if err := json.Unmarshal(data, &raw); err != nil {
@@ -96,7 +97,7 @@ func (e *ExperimentDetail) DeJSON(data []byte, client ClientInterface) (Model, e
 	return detail, nil
 }
 
-// DeList deserializes a list of ExperimentDetails
+// DeList deserializes a list of ExperimentDetails from JSON data.
 func (e *ExperimentDetail) DeList(data []byte, client ClientInterface) ([]Model, error) {
 	var rawList []json.RawMessage
 	if err := json.Unmarshal(data, &rawList); err != nil {
@@ -114,7 +115,7 @@ func (e *ExperimentDetail) DeList(data []byte, client ClientInterface) ([]Model,
 	return result, nil
 }
 
-// Permissions represents user permissions
+// Permissions represents user permissions.
 type Permissions struct {
 	BaseModel
 	CanPlay           bool `json:"can_play"`
@@ -129,7 +130,7 @@ type Permissions struct {
 	CanUseLossless    bool `json:"can_use_lossless"`
 }
 
-// DeJSON deserializes Permissions from JSON
+// DeJSON deserializes Permissions from JSON data.
 func (p *Permissions) DeJSON(data []byte, client ClientInterface) (Model, error) {
 	var raw map[string]json.RawMessage
 	if err := json.Unmarshal(data, &raw); err != nil {
@@ -172,7 +173,7 @@ func (p *Permissions) DeJSON(data []byte, client ClientInterface) (Model, error)
 	return perms, nil
 }
 
-// DeList deserializes a list of Permissions
+// DeList deserializes a list of Permissions from JSON data.
 func (p *Permissions) DeList(data []byte, client ClientInterface) ([]Model, error) {
 	var rawList []json.RawMessage
 	if err := json.Unmarshal(data, &rawList); err != nil {
@@ -190,14 +191,14 @@ func (p *Permissions) DeList(data []byte, client ClientInterface) ([]Model, erro
 	return result, nil
 }
 
-// PermissionAlerts represents permission alerts
+// PermissionAlerts represents permission alerts.
 type PermissionAlerts struct {
 	BaseModel
 	Alerts []PermissionAlert `json:"alerts"`
 	Total  int               `json:"total"`
 }
 
-// DeJSON deserializes PermissionAlerts from JSON
+// DeJSON deserializes PermissionAlerts from JSON data.
 func (p *PermissionAlerts) DeJSON(data []byte, client ClientInterface) (Model, error) {
 	var raw map[string]json.RawMessage
 	if err := json.Unmarshal(data, &raw); err != nil {
@@ -218,7 +219,7 @@ func (p *PermissionAlerts) DeJSON(data []byte, client ClientInterface) (Model, e
 	return alerts, nil
 }
 
-// DeList deserializes a list of PermissionAlerts
+// DeList deserializes a list of PermissionAlerts from JSON data. from JSON data.
 func (p *PermissionAlerts) DeList(data []byte, client ClientInterface) ([]Model, error) {
 	var rawList []json.RawMessage
 	if err := json.Unmarshal(data, &rawList); err != nil {
@@ -236,7 +237,7 @@ func (p *PermissionAlerts) DeList(data []byte, client ClientInterface) ([]Model,
 	return result, nil
 }
 
-// PermissionAlert represents a permission alert
+// PermissionAlert represents a permission alert.
 type PermissionAlert struct {
 	BaseModel
 	ID          string `json:"id"`
@@ -248,7 +249,7 @@ type PermissionAlert struct {
 	CreatedAt   string `json:"created_at"`
 }
 
-// DeJSON deserializes PermissionAlert from JSON
+// DeJSON deserializes PermissionAlert from JSON data.
 func (p *PermissionAlert) DeJSON(data []byte, client ClientInterface) (Model, error) {
 	var raw map[string]json.RawMessage
 	if err := json.Unmarshal(data, &raw); err != nil {
@@ -300,7 +301,7 @@ func (p *PermissionAlert) DeList(data []byte, client ClientInterface) ([]Model,
 	return result, nil
 }
 
-// ContentRestrictions represents content restrictions
+// ContentRestrictions represents content restrictions.
 type ContentRestrictions struct {
 	BaseModel
 	HasExplicitContent bool     `json:"has_explicit_content"`
@@ -311,7 +312,7 @@ type ContentRestrictions struct {
 	BlockedArtists     []string `json:"blocked_artists"`
 }
 
-// DeJSON deserializes ContentRestrictions from JSON
+// DeJSON deserializes ContentRestrictions from JSON data.
 func (c *ContentRestrictions) DeJSON(data []byte, client ClientInterface) (Model, error) {
 	var raw map[string]json.RawMessage
 	if err := json.Unmarshal(data, &raw); err != nil {
@@ -342,7 +343,7 @@ func (c *ContentRestrictions) DeJSON(data []byte, client ClientInterface) (Model
 	return restrictions, nil
 }
 
-// DeList deserializes a list of ContentRestrictions
+// DeList deserializes a list of ContentRestrictions from JSON data.
 func (c *ContentRestrictions) DeList(data []byte, client ClientInterface) ([]Model, error) {
 	var rawList []json.RawMessage
 	if err := json.Unmarshal(data, &rawList); err != nil {