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/client/radio.go

@@ -1,3 +1,4 @@
+// Package client provides methods for interacting with Yandex Music API endpoints.
 package client
 
 import (
@@ -7,7 +8,7 @@ import (
 	"gitea.mrixs.me/Mrixs/yandex-music-api-go/internal/models"
 )
 
-// GetRadioStations gets radio stations
+// GetRadioStations gets radio stations (GET /radio/stations).
 func (c *Client) GetRadioStations(ctx context.Context) ([]*models.RadioStation, error) {
 	var result []models.RadioStation
 	if err := c.request.Get(ctx, "/radio/stations", nil, &result); err != nil {
@@ -22,8 +23,7 @@ func (c *Client) GetRadioStations(ctx context.Context) ([]*models.RadioStation,
 	return stations, nil
 }
 
-// GetRadioStation gets a radio station by ID
-// GET /rotor/station/{stationID}/info
+// GetRadioStation gets a radio station by ID (GET /rotor/station/{stationID}/info).
 func (c *Client) GetRadioStation(ctx context.Context, stationID string) (*models.RadioStation, error) {
 	var result models.RadioStation
 	if err := c.request.Get(ctx, fmt.Sprintf("/rotor/station/%s/info", stationID), nil, &result); err != nil {
@@ -33,8 +33,7 @@ func (c *Client) GetRadioStation(ctx context.Context, stationID string) (*models
 	return &result, nil
 }
 
-// GetStationTracks gets tracks for a radio station
-// GET /rotor/station/{stationID}/tracks
+// GetStationTracks gets tracks for a radio station (GET /rotor/station/{stationID}/tracks).
 func (c *Client) GetStationTracks(ctx context.Context, stationID string, limit int) (*models.StationTracksResult, error) {
 	params := map[string]string{}
 	if limit > 0 {
@@ -48,7 +47,7 @@ func (c *Client) GetStationTracks(ctx context.Context, stationID string, limit i
 	return &result, nil
 }
 
-// GetRotorStations gets rotor stations (generative)
+// GetRotorStations gets rotor stations (generative stations) (GET /rotor/stations).
 func (c *Client) GetRotorStations(ctx context.Context) ([]*models.RotorStation, error) {
 	var result []models.RotorStation
 	if err := c.request.Get(ctx, "/rotor/stations", nil, &result); err != nil {
@@ -63,8 +62,7 @@ func (c *Client) GetRotorStations(ctx context.Context) ([]*models.RotorStation,
 	return stations, nil
 }
 
-// GetRotorStation gets a rotor station by ID
-// GET /rotor/station/{stationID}/info
+// GetRotorStation gets a rotor station by ID (GET /rotor/station/{stationID}/info).
 func (c *Client) GetRotorStation(ctx context.Context, stationID string) (*models.RotorStation, error) {
 	var result models.RotorStation
 	if err := c.request.Get(ctx, fmt.Sprintf("/rotor/station/%s/info", stationID), nil, &result); err != nil {
@@ -74,8 +72,7 @@ func (c *Client) GetRotorStation(ctx context.Context, stationID string) (*models
 	return &result, nil
 }
 
-// GetRotorStationTracks gets tracks for a rotor station
-// GET /rotor/station/{stationID}/tracks
+// GetRotorStationTracks gets tracks for a rotor station (GET /rotor/station/{stationID}/tracks).
 func (c *Client) GetRotorStationTracks(ctx context.Context, stationID string, limit int) (*models.RotorStationTracksResult, error) {
 	params := map[string]string{}
 	if limit > 0 {
@@ -89,8 +86,7 @@ func (c *Client) GetRotorStationTracks(ctx context.Context, stationID string, li
 	return &result, nil
 }
 
-// StartRotorSession starts a rotor session
-// POST /rotor/station/{stationID}/session/start
+// StartRotorSession starts a rotor session (POST /rotor/station/{stationID}/session/start).
 func (c *Client) StartRotorSession(ctx context.Context, stationID string) (*models.RotorSession, error) {
 	var result models.RotorSession
 	if err := c.request.Post(ctx, fmt.Sprintf("/rotor/station/%s/session/start", stationID), nil, &result); err != nil {
@@ -100,8 +96,7 @@ func (c *Client) StartRotorSession(ctx context.Context, stationID string) (*mode
 	return &result, nil
 }
 
-// GetRotorSession gets rotor session info
-// GET /rotor/session?session_id={sessionID}
+// GetRotorSession gets rotor session info by session ID (GET /rotor/session).
 func (c *Client) GetRotorSession(ctx context.Context, sessionID string) (*models.RotorSession, error) {
 	params := map[string]string{
 		"session_id": sessionID,
@@ -115,8 +110,8 @@ func (c *Client) GetRotorSession(ctx context.Context, sessionID string) (*models
 	return &result, nil
 }
 
-// RotorSessionFeedback sends feedback for a rotor session track
-// POST /rotor/station/{stationID}/feedback
+// RotorSessionFeedback sends feedback for a rotor session track (POST /rotor/station/{stationID}/feedback).
+// The feedbackType parameter can be "like", "dislike", or "skip".
 func (c *Client) RotorSessionFeedback(ctx context.Context, sessionID, trackID, feedbackType string) error {
 	params := map[string]string{
 		"track_id": trackID,