feat(completion): improve SQL function suggestions

apps/desktop/src/lib/sql/sqlCompletionLookupTarget.ts

@@ -7,6 +7,11 @@ export interface SqlCompletionTableLookupTarget {
   qualifierDatabase?: string;
 }
 
+export interface SqlCompletionRoutineLookupTarget {
+  schema?: string;
+  mask: string;
+}
+
 function findExactName(names: readonly string[] | undefined, value: string): string | undefined {
   return names?.find((name) => name.toLowerCase() === value.toLowerCase());
 }
@@ -40,3 +45,15 @@ export function resolveSqlCompletionTableLookupTarget(options: {
     filter: qualifier && completionContext.suggestTables ? completionContext.prefix : qualifier || completionContext.prefix,
   };
 }
+
+export function resolveSqlCompletionRoutineLookupTarget(options: { currentSchema?: string; completionContext: Pick<SqlCompletionContext, "qualifier" | "qualifierParts" | "prefix"> }): SqlCompletionRoutineLookupTarget {
+  const qualifierParts = options.completionContext.qualifierParts?.filter(Boolean);
+  const schema = qualifierParts?.[qualifierParts.length - 1] ?? options.completionContext.qualifier?.trim() ?? options.currentSchema;
+
+  // A qualified routine uses the qualifier as metadata scope; only the final
+  // identifier fragment is the function/procedure name mask.
+  return {
+    schema: schema || undefined,
+    mask: options.completionContext.prefix,
+  };
+}