feat: web automation wrapper (#1349), DATALINK table on web, System theme; honest decode accounting

Ported from 2c38de53 (#1717). Main already carries the hatch PDF draw
order fix (#1345), the numeric set_properties compare (#1348) and the
web open from bytes, so those parts stay out; what remains:

#1349 — window.ocsControl.ready/request promise wrapper with an
ocs-ready event (web/ocs-control.js, loaded by the web page), and the
startup donation prompt is suppressed once a control request is seen
(opt-in pre-boot via localStorage["opencadstudio.automation"] = "1").
docs/automation/web.md documents both. The control protocol stays at 1.

DATALINK CSV-to-table works on web (picker + bytes through the session
registry — was std::fs, silently dead); COLORSCHEME accepts System
(prefers-color-scheme on web, AppsUseLightTheme on Windows).

Decode accounting, made honest per the fix-of-fix review: into_rgba8
allocates the RGBA destination while the native buffer is alive for
every non-Rgba8 layout (L8 5, La8 6, Rgb8 7, L16 6, La16 8 B/px
peaks — the formula now says so), GIF bills the screen+frame
coexistence at 8 B/px, and TIFF drops the 3x multipliers both ways —
tiff 0.11 splits the given budget between frame and scratch (a total
ceiling), so the old double-billing refused honest 16-bit GeoTIFFs
~2.25x early while admitting hostile chunk transients at 3x.

(cherry picked from commit 2c38de53)

src/locale_catalog.rs

@@ -1013,6 +1013,7 @@ pub(super) fn message_attribute(source: &str) -> Option<(&'static str, &'static
         "Color Temperature" => Some(("properties", "color-temperature")),
         "Color override (#RRGGBB):" => Some(("styles", "color-override-rrggbb")),
         "Color scheme set to '{name}'." => Some(("view", "color-scheme-set-to-name")),
+        "Color scheme set to 'System' (currently {name})." => Some(("view", "color-scheme-set-to-system-currently-name")),
         "Color {}" => Some(("ui", "color")),
         "Column count" => Some(("properties", "column-count")),
         "Column gutter" => Some(("properties", "column-gutter")),
@@ -4187,6 +4188,8 @@ pub(super) fn message_attribute(source: &str) -> Option<(&'static str, &'static
         "Data Extraction Settings" => Some(("common", "data-extraction-settings")),
         "Add Drawings" => Some(("common", "add-drawings")),
         "CSV" => Some(("common", "csv")),
+        "CSV Files" => Some(("common", "csv-files")),
+        "Link a CSV data source" => Some(("common", "link-a-csv-data-source")),
         "Pick the file again to load its contents in the browser." => Some(("file", "pick-the-file-again-to-load-its-contents")),
         "Adding folders is not available in the browser. Add drawing files instead." => Some(("file", "adding-folders-is-not-available-in-the-browser")),
         "Drawing not loaded in the browser: {name}." => Some(("file", "drawing-not-loaded-in-the-browser")),