Fix OpenCode slash command bridge (#483)

Add a first-class OpenCode command bridge across builds, installs, updates, linked installs, and pinned shortcuts. Preserve current provider behavior while backfilling missing or drifted command files.\n\nAI assistance: contributor and maintainer work used AI tools as disclosed in the PR discussion and commits.

scripts/build.js

@@ -20,6 +20,7 @@ import path from 'path';
 import fs from 'fs';
 import { fileURLToPath } from 'url';
 import { readSourceFiles, readPatterns, stashPerProjectArtifacts, restorePerProjectArtifacts } from './lib/utils.js';
+import { syncRootCommands } from './lib/root-commands-sync.mjs';
 import { createTransformer, PROVIDERS } from './lib/transformers/index.js';
 import { hooksJsonFor, buildClaudePluginHooksManifest } from './lib/transformers/hooks.js';
 import { createAllZips, createProviderZip } from './lib/zip.js';
@@ -657,6 +658,11 @@ async function build() {
       }
     }
 
+    const syncedCommands = syncRootCommands(DIST_DIR, ROOT_DIR, syncConfigs);
+    if (syncedCommands.length > 0) {
+      console.log(`📟 Synced provider commands to: ${syncedCommands.join(', ')}`);
+    }
+
     const syncedHooks = syncRootHookManifests(ROOT_DIR);
     if (syncedHooks.length > 0) {
       console.log(`🪝 Synced hook manifests to: ${syncedHooks.join(', ')}`);