feat: Implement efficient node lookup table using node indices (#463)

Major Changes:
- Add generic Lookup<T> structure for efficient O(1) module-level data access
- Combine separate scope and order lookups into unified QuerySchedule structure
- Add query_schedule field to Interpreter for dedicated user query scheduling
- Refactor loop hoising to separate module
- Use efficient lookup for loop vars
- Also added more tests for loops

Key Concept:
- Ensure module context and indexing stay synchronized during function calls

Testing:
- All scheduler and interpreter tests passing

Signed-off-by: Anand Krishnamoorthi <anakrish@microsoft.com>

src/parser.rs

@@ -1972,4 +1972,14 @@ impl<'source> Parser<'source> {
         }
         Ok(query)
     }
+
+    pub fn num_expressions(&self) -> u32 {
+        self.eidx
+    }
+    pub fn num_statements(&self) -> u32 {
+        self.sidx
+    }
+    pub fn num_queries(&self) -> u32 {
+        self.qidx
+    }
 }