Fix all ty diagnostics on ifcviewer-wgpu (ci-lint ty-ios + ty-bonsai)

This branch carried v0.8.0's strict `[tool.ty.rules] all = "error"` config but
not the source fixes that were made upstream to satisfy it, so both ci-lint ty
gates were failing: `poe ty-ios` reported 256 diagnostics and `poe ty-bonsai`
258. Both are now clean.

Most fixes are ported from v0.8.0 and follow two idioms: initialise a name
before a conditional that may not bind it (plus an `assert` where the invariant
is real but not provable), and close an exhaustive `if`/`elif` chain with
`else: assert False, <discriminant>`.

The branch's own newer accessors are preserved throughout - `.file`,
`.declaration`, `file.types()`, `get_max_id()` are kept rather than reverted to
`wrapped_data.*`, and non-ty upstream changes (notably the in-progress geometry
cache removal) are deliberately not pulled in.

Notable fixes that are not straight ports:

* ifcopenshell_wrapper.pyi: `entity_instance.file` was declared as
  `def file(self) -> file`, where the property name shadows the `class file`
  below it, so the annotation resolved to `Unknown`. Every `element.file` in
  the codebase was therefore unchecked. Qualifying it to `ifcopenshell.file`
  restores `.schema` to its Literal union and surfaces no new diagnostics.

* model/wall.py: a duplicated merge fragment in the void-straddle path ran an
  always-true `if void_straddles:` that read `new_opening` from the mutually
  exclusive branch (stale value, or NameError on the first iteration), followed
  by an unreachable duplicate `elif`. Removing it makes the file match v0.8.0.

* light/operator.py: upstream's own fix unpacks three targets from two values
  and raises ValueError unconditionally; corrected to `None, None, None`.

* assign_system.py, validate.py, geom/main.py: walrus-in-genexp is valid at
  runtime (PEP 572 binds in the containing scope) but ty does not model it;
  rewritten as explicit loops, matching upstream.

Verified: poe ty-ios, poe ty-bonsai, ruff check src/ nix/, black --check .,
and compileall -W error at py3.10 (ifcopenshell-python) and py3.11 (bonsai).

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/ifc5d/ifc5d/csv2ifc.py

@@ -82,6 +82,11 @@ MAIN_CSV_HEADER_COLUMNS.extend(
 )
 
 
+class CostRate(TypedDict):
+    Schedule: str | None
+    RateID: str | None
+
+
 class CostItem(TypedDict):
     children: list[CostItem]
     ifc: NotRequired[ifcopenshell.entity_instance]
@@ -97,6 +102,7 @@ class CostItem(TypedDict):
     Property: Union[str, None]
     Query: Union[str, None]
 
+    CostRate: CostRate | None
     Formula: Union[str, None]
     # QuantityClass: Union[str, None]
 
@@ -239,7 +245,7 @@ class Csv2Ifc:
             cost_values = float(cost_values) if cost_values else None
 
         if self.has_rates:
-            cost_rate = {
+            cost_rate: CostRate = {
                 "Schedule": row[(self.headers["RateSchedule"])] if "RateSchedule" in self.headers else None,
                 "RateID": row[(self.headers["RateID"])] if "RateID" in self.headers else None,
             }

src/ifc5d/ifc5d/ifc2json.py

@@ -109,6 +109,8 @@ class ifc5D2json:
             values = root_element.CostValues
         elif root_element.is_a("IfcConstructionResource"):
             values = root_element.BaseCosts
+        else:
+            assert False, root_element
         for cost_value in values or []:
             self.extract_cost_value(root_element, data, cost_value)
             # data["CostValues"].append(cost_value.id())

src/ifc5d/ifc5d/ifc5Dspreadsheet.py

@@ -26,7 +26,8 @@ import logging
 import os
 import time
 from collections import Counter
-from typing import Optional, TypedDict, Union
+from typing import Optional, Union
+from typing_extensions import TypedDict
 
 import ifcopenshell
 import ifcopenshell.util.cost
@@ -35,7 +36,7 @@ import ifcopenshell.util.element
 import ifcopenshell.util.unit
 
 
-class CostItem(TypedDict):
+class CostItem(TypedDict, extra_items=float):
     # Exported columns.
     Index: int
     Hierarchy: str
@@ -536,6 +537,8 @@ class Ifc5DOdsWriter(Ifc5Dwriter):
                 cell.addElement(P(text=value))
             elif type == "formula":
                 cell = TableCell(formula=value, stylename=style)
+            else:
+                assert False, type
             row.addElement(cell)
 
         first_data_row = 6  # 3 metadata rows, 1 blank row, 1 header row.
@@ -775,6 +778,8 @@ if __name__ == "__main__":
         writer = Ifc5DOdsWriter(args["input"], args["output"])
     elif args["format"] == "XLSX":
         writer = Ifc5DXlsxWriter(args["input"], args["output"])
+    else:
+        assert False, args
     writer.write()
 
     logger.info("Finished conversion in %ss", time.time() - start)

src/ifc5d/pyproject.toml

@@ -17,6 +17,7 @@ classifiers = [
 ]
 dependencies = [
     "ifcopenshell",
+    "typing_extensions",
 ]
 
  [project.optional-dependencies]