Add struct literals, generics, log/print stdlib registration, activate DB wiring

- Register print/println/log/print_err in TypeEnv::with_builtins() with polymorphic (Unknown) param type so any value type is accepted without spurious warnings
- Add StructLit expr to AST + parser (uppercase-IDENT { ... } syntax), BuildStruct bytecode instruction + Struct value to runtime
- Add type_params to FnDef AST node and TypeParam variant to TypeExpr; parser parses <T, E> generics; type checker treats TypeParam as Unknown (universal type)
- Rewrite interpreter to support user-defined function calls via call stack (Frame + return_ip); dispatch_builtin handles print/println/log/print_err/__build_list__
- Fix engram_activate_search to unwrap { results: [...] } response envelope from /search; use std::net for sync HTTP to avoid reqwest dependency
- Add run-file command to CLI for single-file execution without el.toml
- Fix worktree engram-crypto path dep

crates/el-test/src/eval.rs

@@ -304,6 +304,15 @@ impl<'g> Evaluator<'g> {
                 }
                 Ok(EvalValue::Nil)
             }
+
+            Expr::StructLit { type_name: _, fields, .. } => {
+                // Evaluate all fields but return Nil — struct construction in test
+                // eval context is not supported yet (tests use activate, not literals)
+                for (_, e) in fields {
+                    self.eval_expr(e)?;
+                }
+                Ok(EvalValue::Nil)
+            }
         }
     }