feat(client): sync --force to escape the locally-modified skip

Managed items with local modifications were kept (skip + warn) with no
escape hatch other than deleting the deployed file by hand — after an
upstream change the deployed content silently stayed old, which reads
exactly like a stale cache.

--force turns the two skip cases into update (repository version wins)
and remove (upstream deleted + modified). Unmanaged items and never-
managed path occupancies stay untouched even with --force; the default
behavior is unchanged.

internal/cli/sync.go

@@ -10,6 +10,7 @@ import (
 
 func newSyncCmd() *cobra.Command {
 	var configPath, repoURL, ref string
+	var force bool
 	cmd := &cobra.Command{
 		Use:   "sync",
 		Short: "Pull the work repository and deploy its content to OpenCode",
@@ -17,10 +18,13 @@ func newSyncCmd() *cobra.Command {
 			"into the OpenCode runtime paths. The repository comes from --repo, " +
 			"or from the config chain: --config, " + client.ConfigEnv + " env, the " +
 			"user-level config, or the admin-protected platform default. " +
-			"Idempotent: re-running changes nothing when content and disk match.",
+			"Idempotent: re-running changes nothing when content and disk match. " +
+			"Locally modified managed items are kept by default (skip + warn); " +
+			"--force overwrites them with the repository version and removes " +
+			"them after upstream deletion. Unmanaged items are never touched.",
 		Args: cobra.NoArgs,
 		RunE: func(cmd *cobra.Command, args []string) error {
-			opts := client.SyncOptions{ConfigPath: configPath, RepoURL: repoURL, Ref: ref}
+			opts := client.SyncOptions{ConfigPath: configPath, RepoURL: repoURL, Ref: ref, Force: force}
 			if _, err := client.Sync(opts, cmd.OutOrStdout()); err != nil {
 				return fmt.Errorf("sync: %w", err)
 			}
@@ -30,5 +34,6 @@ func newSyncCmd() *cobra.Command {
 	cmd.Flags().StringVar(&configPath, "config", "", "client config path (default: "+client.ConfigEnv+" env, user config, or platform default)")
 	cmd.Flags().StringVar(&repoURL, "repo", "", "work repository URL or path — overrides any config, works without one")
 	cmd.Flags().StringVar(&ref, "ref", "", "branch or tag to pull (requires --repo)")
+	cmd.Flags().BoolVar(&force, "force", false, "overwrite locally modified managed items with the repository version; unmanaged items are never touched")
 	return cmd
 }