feat: hatch PDF draw order (#1345), numeric CAS (#1348), web automation (#1349), DATALINK table, System theme; honest decode accounting

Upstream issues, fixed:

#1345 — hatches plotted at draw_depth 0.0: the plot path cloned models
from the hatch cache, which bakes the depth at seed time; the canvas
re-reads the live depth map every frame, which is why the editor was
right and every export (PDF and native printing — both route through
the exporter) was wrong, with hatch-vs-hatch ties broken by HashMap
order. The plot path now re-reads the depth map per entity, and the
exporter's tie-break ranks follow the editor's own pass order
(hatch < image < wire fill < wire < text < wipeout) instead of pinning
hatches between fills and wires. Pinned by content-stream operator-
order tests (back/front hatches, overlapping hatches, interleaved
wire-between-hatches) and a scene test that fails pre-fix.

#1348 — set_properties' optimistic-concurrency compare now matches
numbers by value (10.0 == 10) through json_values_match, compatible
with the shape of upstream PR #1350; nested objects/arrays recurse.

#1349 — web automation contract: control protocol 2 (v1 clients still
accepted) adds {op:'open', name, data_base64} routed through the
guarded open queue; window.ocsControl.ready/request promise wrapper
with an ocs-ready event (web/ocs-control.js); the startup donation
prompt is suppressed once a control request is seen (opt-in pre-boot
via localStorage); docs/automation documents the whole web contract.

Also: 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. The
image-refusal-unknown-size locale key moves to the group the catalog
always claimed (file).

web-app.html

@@ -44,6 +44,7 @@
     <link data-trunk rel="copy-file" href="web/discussions.json" />
     <link data-trunk rel="copy-file" href="web/videos.json" />
     <link data-trunk rel="copy-file" href="web/locale-labels.json" />
+    <link data-trunk rel="copy-file" href="web/ocs-control.js" />
   </head>
   <body>
     <div id="loading">
@@ -51,6 +52,7 @@
       <div class="title">Open <span>CAD</span> Studio</div>
       <div class="sub">Loading…</div>
     </div>
+    <script src="ocs-control.js" defer></script>
     <script>
       (() => {
         const splash = document.getElementById("loading");