Part of #490 part 2: plugin panels register with authoredGeometryRevision
hard-coded to 0, so a plugin author who ships a new authored panel size
(MossTank: 856x236 -> 984x271) has no way to signal the change short of
adding a manual revision-bump call site, and every user's stored layout
keeps the old size forever. Built-in retail-imported windows solve this
with an explicit incrementing int literal at each Register call; a plugin
author does not maintain that call site by hand.
RetailWindowManager.ComputeAuthoredGeometryRevision derives the revision
from the authored geometry tuple itself (width, height, minw, minh,
resizable) via a fixed FNV-1a-style combine over the values' raw IEEE-754
bit patterns -- deliberately not System.HashCode, whose per-process reseed
would make the "same" authored geometry hash differently on every launch.
The sign bit is masked off so the result is never negative (Register's own
Math.Max(0, revision) would otherwise silently fold distinct negative
hashes onto the same "unversioned" 0 bucket used by legacy saves).
Mutation shown to fail first: without this method,
RetailWindowManagerTests.ComputeAuthoredGeometryRevision_* (7 new tests)
fails to compile (CS0117, method does not exist). No wiring yet -- this
commit only adds the pure, inert helper; MountPlugins still passes no
revision. That lands next along with the comparison-semantics fix it
depends on.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
b2e68c2343