feat(cli): add --vault option for daemon and mirror commands

Allow specifying a separate vault directory for .md files, decoupled from
the database directory (where PouchDB data lives).

- Add --vault/-V flag to CLI options parser
- Use vaultPath (or fallback to databasePath) for file system operations
- Works with both daemon and mirror commands
- Log vault path alongside database path at startup

src/apps/cli/commands/types.ts

@@ -30,6 +30,7 @@ export type CLICommand =
 
 export interface CLIOptions {
     databasePath?: string;
+    vaultPath?: string;
     settingsPath?: string;
     verbose?: boolean;
     debug?: boolean;