F15: correct docstring accuracy from adversarial verify pass (#314)

Follow-up to the macro conversion: an adversarial verify pass (one agent per
file vs. the C++ implementation + stubs) found 62 content issues; the real
ones are fixed here.

Callbacks (centralized):
- on_click: receives (pos, MouseButton, InputState), not str (8 files).
- on_enter/on_exit/on_move (UIBase.h): hover passes only (pos) -- removed the
  fictional button/action args.
- bounds/global_bounds (UIBase.h): mark (tuple, read-only).

Signatures / types:
- Grid.find_path: document heuristic + weight; get_dijkstra_map: document roots;
  compute_fov: FOV | int = FOV.BASIC (not the C constant FOV_BASIC) + Returns;
  at/is_in_fov: document (pos) and (x, y) call forms.
- get_metrics: document all 16 returned dict keys (was 8); bresenham: drop the
  bogus '*' keyword-only separator.
- Nullable defaults typed correctly: BSP seed/size, ColorLayer draw_fov/
  apply_perspective Color|None, Entity.visible_entities radius int=-1 (None is
  rejected by the 'i' parser -> see #319).
- Type-token fixes: GridView.center -> Vector; GridView.texture -> (None,
  read-only) (unimplemented, #318); GridPoint.grid_pos -> (tuple, read-only);
  EntityCollection.find -> Entity | list[Entity] | None; extend RuntimeError;
  UniformCollection.values -> list[float | tuple | None].
- automation: onScreen (x, y) form documented; scroll notes x is ignored (#317).

Also: correct stale AStarPath/DijkstraMap signatures in docs/api-audit-2026-04.md
(the bindings were right, the audit table was outdated). Rebaseline the API
snapshot golden and regenerate docs/stubs.

Code-level bugs surfaced by the pass are filed as #317, #318, #319.

Refs #314, #317, #318, #319

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/UIGridPoint.cpp

@@ -143,7 +143,7 @@ PyGetSetDef UIGridPoint::getsetters[] = {
     {"entities", (getter)UIGridPoint::get_entities, NULL,
      MCRF_PROPERTY(entities, "List of Entity objects currently occupying this cell (list, read-only)."), NULL},
     {"grid_pos", (getter)UIGridPoint::get_grid_pos, NULL,
-     MCRF_PROPERTY(grid_pos, "Grid coordinates as (x, y) tuple (read-only)."), NULL},
+     MCRF_PROPERTY(grid_pos, "Grid coordinates as an (x, y) position (tuple, read-only)."), NULL},
     {NULL}  /* Sentinel */
 };