[rush][rush-published-versions-json-plugin] Add plugin-native global commands; add published versions JSON plugin.

[iclanton]

Summary

This PR makes two related changes:

1. Extends the Rush plugin API to allow plugins to implement native global commands without requiring a shell script. Previously, global commands always required a shellCommand — plugins had no way to run their own code directly.

2. Adds @rushstack/rush-published-versions-json-plugin, a new Rush plugin that generates a JSON file recording the version numbers of all published packages in a monorepo. Usage: rush record-published-versions --output-path <path>. This plugin is also the first consumer of the new API, serving as a reference implementation.

Details

Rush plugin API changes (@microsoft/rush-lib):

• New "globalPlugin" command kind: A new commandKind value for command-line.json that can only be used in plugin-provided command-line.json files. Unlike "global" commands, "globalPlugin" commands have no shellCommand or autoinstallerName — the implementation is provided entirely by the plugin's code via the runGlobalCustomCommand hook. If a repo user tries to use "globalPlugin" in the repo's command-line.json, Rush rejects it with a clear error. At runtime, "globalPlugin" is normalized to a "global" command with an empty shell command and an isPluginOnly flag (similar to how "bulk" commands are normalized to "phased").
• Added getCustomParametersByLongName() to IGlobalCommand, giving plugin hooks access to parsed command-line parameter values (e.g. --output-path). Parameters are keyed by long name and return CommandLineParameter objects from @rushstack/ts-command-line.
• Added setHandled() to IGlobalCommand. When a plugin hook calls this, the default shell command execution is skipped. If a "globalPlugin" command runs but no plugin calls setHandled(), Rush throws a clear error indicating the plugin is not properly handling the command.
• Narrowed the beforeInstall hook's command type from IGlobalCommand to IRushCommand, since install/update actions were never global custom commands.

Plugin (@rushstack/rush-published-versions-json-plugin):

• Provides a command-line.json using the new "globalPlugin" command kind for the record-published-versions command, with a required --output-path string parameter.
• The plugin's apply() method taps runGlobalCustomCommand.for('record-published-versions'), calls command.setHandled(), then generates a JSON map of { packageName: version } for all projects with shouldPublish or a versionPolicy.

Design alternatives considered:

• Making shellCommand optional in the JSON schema — rejected because it would let repo users accidentally omit shellCommand and get a command that silently does nothing.
• Using shellCommand: "" with a regular "global" kind — replaced with the dedicated "globalPlugin" kind, which is more explicit, self-documenting, and restricts usage to plugins only. The schema itself acts as a version gate: if Rush is too old to understand "globalPlugin", it fails at schema validation with a clear error.

No backwards compatibility concerns — IGlobalCommand is @beta and the new members are additive. Existing global commands with a shellCommand are unaffected.

How it was tested

• Built @microsoft/rush-lib, @rushstack/rush-sdk, and @rushstack/rush-published-versions-json-plugin with rush build — all pass cleanly with no errors or warnings.
• Verified the API review file (rush-lib.api.md) reflects the expected surface changes (globalPluginCommandKind added to RushConstants).

Impacted documentation

• https://rushjs.io/pages/maintainer/custom_commands/ (documents commandKind values — should add "globalPlugin" for plugin-native global commands)
• https://rushjs.io/pages/maintainer/using_rush_plugins/ (could mention plugin-native global commands as a capability)