feat: composer improvements

backend/uframe/ir.py

@@ -302,6 +302,9 @@ class SourceType(Enum):
     PYTHON = auto()
     RNS = auto()
     PARAM = auto()
+    HTTP = auto()
+    SQLITE = auto()
+    ENV = auto()
 
 
 @dataclass
@@ -317,6 +320,12 @@ class Source(IRNode):
     var_name: str = ""
     source_type: SourceType = SourceType.SHELL
     command: str = ""
+    # HTTP-specific
+    http_method: str = "GET"
+    http_body: str = ""
+    http_headers: str = ""
+    # SQLite-specific: command = db path, query = SQL
+    query: str = ""
     timeout: int = 5