chore(cli): list managed tools in mops toolchain --help and on missing/invalid <tool>

Move the tool list from `bin`'s description into the parent `toolchain`
description, add argument descriptions on `use`/`update`/`bin` so the
choices show under `Arguments:`, and enable `showHelpAfterError()` so a
bare `mops toolchain use` prints the help (with choices) instead of just
`error: missing required argument 'tool'`.

Co-authored-by: Cursor <cursoragent@cursor.com>

Author: Kamirus

cli/CHANGELOG.md

@@ -1,6 +1,8 @@
 # Mops CLI Changelog
 
 ## Next
+- `mops toolchain --help` now lists the tools mops manages (`moc`, `wasmtime`, `pocket-ic`, `lintoko`) in the top-level description instead of only mentioning them under `bin`, and `mops toolchain use` / `update` / `bin` print the available tools (via the auto-generated help) when invoked with a missing or invalid `<tool>` argument.
+
 - Add `--patch` to `mops update` and `mops outdated` to restrict updates to patch versions only (e.g. `1.2.3 -> 1.2.4`, never `1.2.3 -> 1.3.0`). Mutually exclusive with `--major`. For pre-1.0 packages this matches the default — caret already restricts `0.x.y` to patch updates. Useful for risk-averse upgrades on packages that have hit 1.0+.
 
 - Improve the per-file integrity-check error after `mops install --lock update`. Previously the message told users to run `mops install --lock update` — the exact command that just failed. After a regenerated lockfile, the only way a per-file hash can still mismatch is a local edit under `.mops/`, so the message now says that and suggests restoring from the global cache (delete the `.mops/<pkg>` directory and run `mops install`) or using a `repo`/`path` entry in `mops.toml` to keep custom changes.

cli/cli.ts

@@ -674,9 +674,11 @@ program
   });
 
 // toolchain
-const toolchainCommand = new Command("toolchain").description(
-  "Toolchain management",
-);
+const toolchainCommand = new Command("toolchain")
+  .description(
+    `Toolchain management for ${TOOLCHAINS.map((s) => `"${s}"`).join(", ")}`,
+  )
+  .showHelpAfterError();
 
 toolchainCommand
   .command("init")
@@ -695,8 +697,13 @@ toolchainCommand
 toolchainCommand
   .command("use")
   .description("Install specified tool version and update mops.toml")
-  .addArgument(new Argument("<tool>").choices(TOOLCHAINS))
-  .addArgument(new Argument("[version]"))
+  .addArgument(new Argument("<tool>", "tool to install").choices(TOOLCHAINS))
+  .addArgument(
+    new Argument(
+      "[version]",
+      "version to install (defaults to interactive picker)",
+    ),
+  )
   .action(async (tool, version) => {
     if (!checkConfigFile()) {
       process.exit(1);
@@ -709,7 +716,12 @@ toolchainCommand
   .description(
     "Update specified tool or all tools to the latest version and update mops.toml",
   )
-  .addArgument(new Argument("[tool]").choices(TOOLCHAINS))
+  .addArgument(
+    new Argument(
+      "[tool]",
+      "tool to update (defaults to all configured tools)",
+    ).choices(TOOLCHAINS),
+  )
   .action(async (tool?: Tool) => {
     if (!checkConfigFile()) {
       process.exit(1);
@@ -719,10 +731,8 @@ toolchainCommand
 
 toolchainCommand
   .command("bin")
-  .description(
-    `Get path to the tool binary\n<tool> can be one of ${TOOLCHAINS.map((s) => `"${s}"`).join(", ")}`,
-  )
-  .addArgument(new Argument("<tool>").choices(TOOLCHAINS))
+  .description("Get path to the tool binary")
+  .addArgument(new Argument("<tool>", "tool to look up").choices(TOOLCHAINS))
   .addOption(
     new Option(
       "--fallback",