feat(cli): error on vp install -g without package names (#1472)

Currently, running `vp install -g` with no package names will silently
fall through to a regular workspace install, ignoring `--global`
entirely, as the `global` check logic will only happen after checking
package name is provided.

This PR adjusted clap config to make sure package is provided when using
`--global` flag, also adjusted help output for more clear guidance.

Global snap test is also added to cover this case.

Generated with [Claude Code](https://claude.com/claude-code) and Codex

---------

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: liangmiQwQ

crates/vite_global_cli/src/cli.rs

@@ -145,8 +145,8 @@ pub enum Commands {
         #[arg(long)]
         save_catalog: bool,
 
-        /// Install globally (only when adding packages)
-        #[arg(short = 'g', long)]
+        /// Install globally (requires package names)
+        #[arg(short = 'g', long, requires = "packages")]
         global: bool,
 
         /// Node.js version to use for global installation (only with -g)

packages/cli/snap-tests-global/cli-helper-message/snap.txt

@@ -103,7 +103,7 @@ Options:
   --save-peer           Save to peerDependencies (only when adding packages)
   -O, --save-optional   Save to optionalDependencies (only when adding packages)
   --save-catalog        Save the new dependency to the default catalog (only when adding packages)
-  -g, --global          Install globally (only when adding packages)
+  -g, --global          Install globally (requires package names)
   --node <NODE>         Node.js version to use for global installation (only with -g)
   -h, --help            Print help
 

packages/cli/snap-tests-global/command-install-globally-no-args/package.json

@@ -0,0 +1,3 @@
+{
+  "name": "command-install-g-no-args"
+}

packages/cli/snap-tests-global/command-install-globally-no-args/snap.txt

@@ -0,0 +1,7 @@
+[2]> vp install -g # Should error when no packages provided
+error: the following required arguments were not provided:
+  <PACKAGES>...
+
+Usage: vp install --global <PACKAGES>... [-- <PASS_THROUGH_ARGS>...]
+
+For more information, try '--help'.

packages/cli/snap-tests-global/command-install-globally-no-args/steps.json

@@ -0,0 +1,4 @@
+{
+  "env": {},
+  "commands": ["vp install -g # Should error when no packages provided"]
+}