fix(cli): add --yes alias for skills install

Keep the argparse CLI aligned with the slash command so --yes and -y
behave the same as --force for hermes skills install.
Add a parser-level regression test.

tests/hermes_cli/test_skills_install_flags.py

@@ -0,0 +1,26 @@
+import sys
+from types import SimpleNamespace
+
+
+def test_cli_skills_install_accepts_yes_alias(monkeypatch):
+    from hermes_cli.main import main
+
+    captured = {}
+
+    def fake_skills_command(args):
+        captured["identifier"] = args.identifier
+        captured["force"] = args.force
+
+    monkeypatch.setattr("hermes_cli.skills_hub.skills_command", fake_skills_command)
+    monkeypatch.setattr(
+        sys,
+        "argv",
+        ["hermes", "skills", "install", "official/email/agentmail", "--yes"],
+    )
+
+    main()
+
+    assert captured == {
+        "identifier": "official/email/agentmail",
+        "force": True,
+    }