chore: remove license code, fix compilation, update README bilingual

- Remove all license-related code (handler/service/repository/model)
  License authorization is managed by separate server:
  https://github.com/ShukeBta/MediaStationLicenseServer
- Fix compilation errors: model field alignment, method name fixes,
  route conflicts, struct literal corrections (7 files)
- Add Chinese README.md as primary, English README_EN.md
- Update .gitignore: exclude .workbuddy/, editor backups
- Add new repository files: assistant, play_profile, storage_config

internal/service/license.go

@@ -1,160 +0,0 @@
-// Package service — license key management.
-//
-// LicenseService handles offline-friendly key issuance, activation
-// binding, heartbeat tracking, and revocation. Keys are 24 random
-// uppercase chars in groups of four (e.g. ABCD-1234-EFGH-5678-IJKL-90MN)
-// — the same shape the Vue admin UI expects.
-package service
-
-import (
-	"context"
-	"crypto/rand"
-	"errors"
-	"strings"
-	"time"
-
-	"go.uber.org/zap"
-
-	"github.com/ShukeBta/MediaStationGo/internal/model"
-	"github.com/ShukeBta/MediaStationGo/internal/repository"
-)
-
-// LicenseService manages license keys + activations.
-type LicenseService struct {
-	log  *zap.Logger
-	repo *repository.Container
-}
-
-// NewLicenseService is the constructor.
-func NewLicenseService(log *zap.Logger, repo *repository.Container) *LicenseService {
-	return &LicenseService{log: log, repo: repo}
-}
-
-// Generate creates a new license key. ExpiresAt nil means "perpetual".
-func (s *LicenseService) Generate(
-	ctx context.Context,
-	customer, plan, notes string,
-	maxActivations int,
-	expiresAt *time.Time,
-) (*model.LicenseKey, error) {
-	if maxActivations <= 0 {
-		maxActivations = 1
-	}
-	k := &model.LicenseKey{
-		Key:            randomLicenseKey(),
-		Customer:       strings.TrimSpace(customer),
-		Plan:           strings.TrimSpace(plan),
-		MaxActivations: maxActivations,
-		Notes:          strings.TrimSpace(notes),
-		IssuedAt:       time.Now(),
-		ExpiresAt:      expiresAt,
-	}
-	if err := s.repo.License.Create(ctx, k); err != nil {
-		return nil, err
-	}
-	return k, nil
-}
-
-// List returns every key (admin view).
-func (s *LicenseService) List(ctx context.Context) ([]model.LicenseKey, error) {
-	return s.repo.License.List(ctx)
-}
-
-// Activate binds a key to a device. Fails when the key is missing,
-// revoked, expired, or already at MaxActivations.
-func (s *LicenseService) Activate(
-	ctx context.Context,
-	key, deviceID, deviceName, ip string,
-) (*model.LicenseActivation, error) {
-	k, err := s.repo.License.FindByKey(ctx, key)
-	if err != nil {
-		return nil, err
-	}
-	if k == nil {
-		return nil, errors.New("invalid key")
-	}
-	if k.Revoked {
-		return nil, errors.New("key revoked")
-	}
-	if k.ExpiresAt != nil && k.ExpiresAt.Before(time.Now()) {
-		return nil, errors.New("key expired")
-	}
-	count, err := s.repo.License.CountActiveActivations(ctx, k.ID)
-	if err != nil {
-		return nil, err
-	}
-	if int(count) >= k.MaxActivations {
-		return nil, errors.New("activation limit reached")
-	}
-	a := &model.LicenseActivation{
-		KeyID:      k.ID,
-		DeviceID:   strings.TrimSpace(deviceID),
-		DeviceName: strings.TrimSpace(deviceName),
-		IP:         ip,
-	}
-	if err := s.repo.License.AddActivation(ctx, a); err != nil {
-		return nil, err
-	}
-	return a, nil
-}
-
-// ListActivations returns activations for a single key.
-func (s *LicenseService) ListActivations(ctx context.Context, keyID string) ([]model.LicenseActivation, error) {
-	return s.repo.License.ListActivations(ctx, keyID)
-}
-
-// Unbind marks one activation as released.
-func (s *LicenseService) Unbind(ctx context.Context, activationID string) error {
-	return s.repo.License.UnbindActivation(ctx, activationID)
-}
-
-// Revoke marks the entire key as revoked.
-func (s *LicenseService) Revoke(ctx context.Context, keyID string) error {
-	return s.repo.License.Update(ctx, keyID, map[string]any{"revoked": true})
-}
-
-// Heartbeat records the last time an activation phoned home.
-func (s *LicenseService) Heartbeat(ctx context.Context, activationID string) error {
-	return s.repo.License.TouchHeartbeat(ctx, activationID)
-}
-
-// Status returns a summary suitable for the Vue / React status panel.
-func (s *LicenseService) Status(ctx context.Context, keyID string) (map[string]any, error) {
-	k, err := s.repo.License.FindByID(ctx, keyID)
-	if err != nil {
-		return nil, err
-	}
-	if k == nil {
-		return nil, errors.New("key not found")
-	}
-	count, _ := s.repo.License.CountActiveActivations(ctx, keyID)
-	valid := !k.Revoked
-	if k.ExpiresAt != nil && k.ExpiresAt.Before(time.Now()) {
-		valid = false
-	}
-	return map[string]any{
-		"key":                k,
-		"active_activations": count,
-		"valid":              valid,
-	}, nil
-}
-
-// randomLicenseKey produces a 24-char hyphenated key of A-Z and 0-9.
-func randomLicenseKey() string {
-	const alphabet = "ABCDEFGHJKLMNPQRSTUVWXYZ23456789" // omit confusables
-	out := make([]byte, 24)
-	buf := make([]byte, 24)
-	_, _ = rand.Read(buf)
-	for i, b := range buf {
-		out[i] = alphabet[int(b)%len(alphabet)]
-	}
-	// Group every 4 chars with a hyphen.
-	var sb strings.Builder
-	for i, c := range out {
-		if i > 0 && i%4 == 0 {
-			sb.WriteByte('-')
-		}
-		sb.WriteByte(byte(c))
-	}
-	return sb.String()
-}