fix(slashcommand): discover nested opencode commands

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

src/tools/slashcommand/command-discovery.ts

@@ -18,17 +18,31 @@ export interface CommandDiscoveryOptions {
   enabledPluginsOverride?: Record<string, boolean>
 }
 
-function discoverCommandsFromDir(commandsDir: string, scope: CommandScope): CommandInfo[] {
+function discoverCommandsFromDir(
+  commandsDir: string,
+  scope: CommandScope,
+  prefix = "",
+): CommandInfo[] {
   if (!existsSync(commandsDir)) return []
 
   const entries = readdirSync(commandsDir, { withFileTypes: true })
   const commands: CommandInfo[] = []
 
   for (const entry of entries) {
+    if (entry.isDirectory()) {
+      if (entry.name.startsWith(".")) continue
+      const nestedPrefix = prefix ? `${prefix}:${entry.name}` : entry.name
+      commands.push(
+        ...discoverCommandsFromDir(join(commandsDir, entry.name), scope, nestedPrefix),
+      )
+      continue
+    }
+
     if (!isMarkdownFile(entry)) continue
 
     const commandPath = join(commandsDir, entry.name)
-    const commandName = basename(entry.name, ".md")
+    const baseCommandName = basename(entry.name, ".md")
+    const commandName = prefix ? `${prefix}:${baseCommandName}` : baseCommandName
 
     try {
       const content = readFileSync(commandPath, "utf-8")