Refactor cache validation and optimize alignment wizard incremental updates

- Extract cache mismatch logic into reusable cache_mismatch_reasons() function
  for cleaner validation and consistent miss reporting
- Expose memory_budget_bytes() for external callers (aligned exporter)
- Optimize rebuild_stack() with incremental layer updates when only one angle
  parameters change, avoiding full reprojection overhead
- Remove unused seed_per_angle parameter from alignment wizard
- Simplify cached_rf_image() DC masking with cleaner early exit logic
- Clean up internal state tracking with explicit origin caching

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

sras_workers.py

@@ -361,21 +361,17 @@ class CrossCorrelateWorker(_PooledWorker):
     angle_done = pyqtSignal(int, float, float, float, float, str)
 
     def __init__(self, sras: SrasFile, ref_angle_idx: int, angle_indices: list[int],
-                dc4_mv: dict[int, np.ndarray], *,
-                sources: tuple[str, ...], dc_threshold_mv: float,
-                search_deg: float, reg_kwargs: dict | None = None):
-        """*reg_kwargs* is splatted into register_angle_to_reference on top of
-        the named arguments — the wizard's rotation-search controls (seed,
-        signs, refine, grid sizes) go through here, so exposing another knob
-        needs no change to this class."""
+                dc4_mv: dict[int, np.ndarray], *, reg_kwargs: dict | None = None):
+        """*reg_kwargs* is splatted into register_angle_to_reference — every
+        registration setting the wizard exposes (sources, threshold, search
+        width, seed, signs, refine, grid sizes) travels in it, so this class
+        holds no opinion about which knobs exist and exposing another needs no
+        change here."""
         super().__init__()
         self._sras = sras
         self._ref = ref_angle_idx
         self._angles = angle_indices
         self._dc4_mv = dc4_mv
-        self._sources = sources
-        self._threshold = dc_threshold_mv
-        self._search_deg = search_deg
         self._reg_kwargs = dict(reg_kwargs or {})
 
     def _plan(self) -> int:
@@ -386,9 +382,7 @@ class CrossCorrelateWorker(_PooledWorker):
 
     def _one(self, a: int) -> tuple[int, compute.RigidFit]:
         return a, compute.register_angle_to_reference(
-            self._sras, a, self._ref, self._dc4_mv,
-            dc_threshold_mv=self._threshold, sources=self._sources,
-            search_deg=self._search_deg, **self._reg_kwargs)
+            self._sras, a, self._ref, self._dc4_mv, **self._reg_kwargs)
 
     def _emit(self, result):
         a, fit = result