fix: accept idx --version / -V

`idx version` was the only way to get the version; the conventional flag
failed with a usage error. The flag is hidden from help, which keeps
documenting `idx version`. clap's bash completions list hidden flags, so
the completions-bash golden gains -V/--version at the root (intended).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

crates/idx-cli/src/cli/mod.rs

@@ -19,6 +19,8 @@ pub enum Shell {
 #[command(
     name = "idx",
     bin_name = "idx",
+    version,
+    disable_version_flag = true,
     about = "CLI tool for Indonesian stock market (IDX) analysis",
     long_about = "idx-cli is a Rust command-line tool for Indonesian stock market (IDX) analysis.\nIt supports quote lookup, historical data, local caching, and output formats for both humans and AI agents."
 )]
@@ -41,6 +43,9 @@ pub struct Cli {
     pub offline: bool,
     #[arg(long, global = true, help = "Bypass local cache")]
     pub no_cache: bool,
+    // `idx version` is the documented form; `--version` is a hidden alias.
+    #[arg(short = 'V', long, action = clap::ArgAction::Version, hide = true)]
+    version: Option<bool>,
     #[command(subcommand)]
     pub command: Commands,
 }

crates/idx-cli/tests/golden/completions-bash.golden

@@ -439,7 +439,7 @@ _idx() {
 
     case "${cmd}" in
         idx)
-            opts="-o -q -v -h --output --no-color --quiet --verbose --offline --no-cache --help stocks config cache ownership completions version help"
+            opts="-o -q -v -V -h --output --no-color --quiet --verbose --offline --no-cache --version --help stocks config cache ownership completions version help"
             if [[ ${cur} == -* || ${COMP_CWORD} -eq 1 ]] ; then
                 COMPREPLY=( $(compgen -W "${opts}" -- "${cur}") )
                 return 0