feat(command-loader): add slash command loader from multiple paths

Load commands from 4 directory scopes:
- .opencode/command/ (opencode-project)
- .claude/commands/ (project)
- ~/.config/opencode/command/ (opencode)
- ~/.claude/commands/ (user)

🤖 GENERATED WITH ASSISTANCE OF [OhMyOpenCode](https://github.com/code-yeongyu/oh-my-opencode)

src/features/command-loader/loader.ts

@@ -0,0 +1,94 @@
+import { existsSync, readdirSync, readFileSync } from "fs"
+import { homedir } from "os"
+import { join, basename } from "path"
+import { parseFrontmatter } from "../../shared/frontmatter"
+import { sanitizeModelField } from "../../shared/model-sanitizer"
+import type { CommandScope, CommandDefinition, CommandFrontmatter, LoadedCommand } from "./types"
+
+function isMarkdownFile(entry: { name: string; isFile: () => boolean }): boolean {
+  return !entry.name.startsWith(".") && entry.name.endsWith(".md") && entry.isFile()
+}
+
+function loadCommandsFromDir(commandsDir: string, scope: CommandScope): LoadedCommand[] {
+  if (!existsSync(commandsDir)) {
+    return []
+  }
+
+  const entries = readdirSync(commandsDir, { withFileTypes: true })
+  const commands: LoadedCommand[] = []
+
+  for (const entry of entries) {
+    if (!isMarkdownFile(entry)) continue
+
+    const commandPath = join(commandsDir, entry.name)
+    const commandName = basename(entry.name, ".md")
+
+    try {
+      const content = readFileSync(commandPath, "utf-8")
+      const { data, body } = parseFrontmatter<CommandFrontmatter>(content)
+
+      const wrappedTemplate = `<command-instruction>
+${body.trim()}
+</command-instruction>
+
+<user-request>
+$ARGUMENTS
+</user-request>`
+
+      const formattedDescription = `(${scope}) ${data.description || ""}`
+
+      const definition: CommandDefinition = {
+        name: commandName,
+        description: formattedDescription,
+        template: wrappedTemplate,
+        agent: data.agent,
+        model: sanitizeModelField(data.model),
+        subtask: data.subtask,
+        argumentHint: data["argument-hint"],
+      }
+
+      commands.push({
+        name: commandName,
+        path: commandPath,
+        definition,
+        scope,
+      })
+    } catch {
+      continue
+    }
+  }
+
+  return commands
+}
+
+function commandsToRecord(commands: LoadedCommand[]): Record<string, CommandDefinition> {
+  const result: Record<string, CommandDefinition> = {}
+  for (const cmd of commands) {
+    result[cmd.name] = cmd.definition
+  }
+  return result
+}
+
+export function loadUserCommands(): Record<string, CommandDefinition> {
+  const userCommandsDir = join(homedir(), ".claude", "commands")
+  const commands = loadCommandsFromDir(userCommandsDir, "user")
+  return commandsToRecord(commands)
+}
+
+export function loadProjectCommands(): Record<string, CommandDefinition> {
+  const projectCommandsDir = join(process.cwd(), ".claude", "commands")
+  const commands = loadCommandsFromDir(projectCommandsDir, "project")
+  return commandsToRecord(commands)
+}
+
+export function loadOpencodeGlobalCommands(): Record<string, CommandDefinition> {
+  const opencodeCommandsDir = join(homedir(), ".config", "opencode", "command")
+  const commands = loadCommandsFromDir(opencodeCommandsDir, "opencode")
+  return commandsToRecord(commands)
+}
+
+export function loadOpencodeProjectCommands(): Record<string, CommandDefinition> {
+  const opencodeProjectDir = join(process.cwd(), ".opencode", "command")
+  const commands = loadCommandsFromDir(opencodeProjectDir, "opencode-project")
+  return commandsToRecord(commands)
+}