Prepare v1.74.0-beta.3

Seven version sources move together to 1.74.0-beta.3; the changelog
sections in both languages close over what has landed since beta.2, the
release notes carry the two shipped bullets on each side with the grouped
small-fixes bullet last, and STATUS says what this beta is.

What the user gets: dragging the plan is smooth again — a gesture frame
now moves what is already drawn by a composited transform, and the scene
re-rasterizes on a budget (100 ms, or a 15 % shift) instead of on every
frame, which on the owner's 144 Hz Firefox cost 200 ms per frame with the
refresh driver skipping 124-144 ticks a second waiting for paint (#531);
and the printed plan is about a third larger, because the in-plan
dimension labels shrank by a quarter and the separate column of external
dimensions is gone, so the drawing keeps a whole scale step (#530).

The speed verdict for #531 is deliberately not claimed here: headless
Firefox and Chromium hold 60 fps on both the old and the new path, so it
is owed by a profile from the owner's machine on the same pan.

`npm test` 2528/0/1 skip, release contract green on all seven sources,
bundle 287 238 B gzip inside the ceiling, docs strict green.

The `Release:` trailer is what asks CI for the heavy gates — smokes,
golden and the full performance comparison — on this exact SHA (#479).

Issue: #531
User-Visible: yes
Release: v1.74.0-beta.3

src/houseplan-card.ts

@@ -416,7 +416,7 @@ import type { MarkerRoomReferenceSnapshot } from './room-reference-transaction';
 import { SummaryRuntimeSlot, summaryRuntimeLoader } from './summary-runtime-loader';
 import { displayVersion } from './card-version';
 
-const CARD_VERSION = '1.74.0-beta.2';
+const CARD_VERSION = '1.74.0-beta.3';
 const ENTRY_BUILD_FINGERPRINT = '__HOUSEPLAN_SOURCE_FINGERPRINT__';
 const EDITOR_RETRY_ASSET = '__HOUSEPLAN_EDITOR_RETRY_ASSET__';
 const ISO_RETRY_ASSET = '__HOUSEPLAN_ISO_RETRY_ASSET__';

src/houseplan-editor-runtime.ts

@@ -388,7 +388,7 @@ import {
   rewriteMarkerRoomReferences, type MarkerRoomReferenceSnapshot,
 } from './room-reference-transaction';
 
-const CARD_VERSION = '1.74.0-beta.2';
+const CARD_VERSION = '1.74.0-beta.3';
 
 // #474: the editor imports the furniture artwork statically and hands it to
 // the page runtime the moment this chunk evaluates — before the loader's