feat!: Introduce structured destructuring plans for bindings (#485)

- add a dedicated `compiler/destructuring_planner` feature that precomputes binding plans for assignments, parameters, and `some in` expressions
- enrich `ScopeContext` with same-scope tracking, local scheduling hints, and module globals so the planner enforces := shadowing rules without blocking parent scopes
- wire the planner through compiler, hoist, interpreter, and engine paths while updating binding plan variants and adding query traversal helpers for dependency analysis
- document the new planner architecture and ship interpreter regressions that exercise nested destructuring, shadowing, and error reporting

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

tests/interpreter/cases/some/tests.yaml

@@ -76,7 +76,7 @@ cases:
         import future.keywords
         x { some [1] in [[1, 2]] }
     query: data.test
-    error: "array length mismatch. Expected 1 got 2."
+    error: "mismatch in number of array elements"
 
   - note: array-length-mismatch-skipped
     data: {}