fix(bicep): detect param context when module ref has empty version

The lookback regex used ([^']+) requiring one or more version chars,
so 'br/modules:modules/keyvault:' (no version yet) silently fell through
to the unknown context and injected all module names instead of params.

Change + to * to allow empty version string. The param_completion_items
fallback already handles empty version by picking the closest schema.

tests/test_proxy.py

@@ -253,6 +253,22 @@ def test_detect_param_context():
     assert ctx["version"] == "1.1.x"
 
 
+def test_detect_param_context_empty_version():
+    """Params context should work even when module ref has no version yet."""
+    lines = [
+        "module keyVault 'br/modules:modules/keyvault:' = {",
+        "  params: {",
+        "    ",  # ← cursor here
+        "  }",
+        "}",
+    ]
+    session = _make_session_with_doc(URI, lines)
+    ctx = session._detect_context(URI, {"line": 2, "character": 4})
+    assert ctx["type"] == "param"
+    assert ctx["module"] == "modules/keyvault"
+    assert ctx["version"] == ""
+
+
 def test_detect_param_value_context_no_quote():
     """Cursor after 'principalType: ' (no opening quote) → param_value context."""
     lines = [