feat: param_value context — enum/allowed completions for principalType, environmentType etc.

- Add _KNOWN_ENUMS dict (principalType, principalObjectType, environmentType fallbacks)
- Add param_value_completion_items() to BicepModuleCatalog
- Detect 'param_value' context in _detect_context() (cursor after 'param: ' inside params block)
- Wire param_value into _inject_completions()
- 9 new unit tests (context detection, catalog allowed, known enum fallback, injection)
- Fix modules.py edit regression (param_completion_items was orphaned)
- All 35 tests pass

ilsp/bicep_lsp/proxy.py

@@ -127,10 +127,25 @@ class _ProxySession:
             if params_m:
                 text_in_params = text_after_mod[params_m.start():]
                 if text_in_params.count("{") > text_in_params.count("}"):
+                    mod_name = last_mod.group(1)
+                    mod_ver = last_mod.group(2)
+
+                    # Check if cursor is after 'paramname: ' on the current line
+                    # (value context — inject enum/allowed values)
+                    value_m = re.search(r"^\s*(\w+):\s*('?)([^'{}]*)$", current)
+                    if value_m and value_m.group(1) not in {"params", "name", "module", "resource"}:
+                        return {
+                            "type": "param_value",
+                            "module": mod_name,
+                            "version": mod_ver,
+                            "param": value_m.group(1),
+                            "has_open_quote": bool(value_m.group(2)),
+                        }
+
                     return {
                         "type": "param",
-                        "module": last_mod.group(1),
-                        "version": last_mod.group(2),
+                        "module": mod_name,
+                        "version": mod_ver,
                     }
 
         return {"type": "unknown"}
@@ -175,6 +190,13 @@ def _inject_completions(msg: dict[str, Any], context: dict | None = None) -> byt
         lru_items = BicepModuleCatalog.param_completion_items(
             context["module"], context["version"]
         )
+    elif ctx_type == "param_value":
+        lru_items = BicepModuleCatalog.param_value_completion_items(
+            context["module"],
+            context["version"],
+            context["param"],
+            context.get("has_open_quote", False),
+        )
     else:
         # Default: module name completions
         lru_items = BicepModuleCatalog.as_completion_items()