Fix: HtmlBlock sanitizer strips select/meter presentation attrs

size, low, high, and optimum were missing from PURIFY_CONFIG.ALLOWED_ATTR
even though <select> and <meter> are already in ALLOWED_TAGS, so
<select size="4"> rendered at default height and <meter low/high/optimum>
lost its threshold-based gauge colouring. All four are pure
presentation/semantic attributes with no URL/script/event-handler
surface, so no security implication.

Also regenerates the pinned pre-Task-25 output fixture: its source
(html-block-test-body.html) already exercises size/low/high/optimum, so
the byte-identity test's expected output legitimately changes to include
them; verified the regenerated fixture's only diff from the prior one is
those four attributes now surviving.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

craft/src/components/basic/HtmlBlock.tsx

@@ -107,12 +107,20 @@ const PURIFY_CONFIG = {
     // Task 24 additions.
     'colspan','rowspan','scope','headers','span','start','reversed',
     'type','value','name','placeholder','required','disabled','readonly',
-    'checked','selected','multiple','min','max','step','minlength',
+    'checked','selected','multiple','size','min','max','step','minlength',
     'maxlength','pattern','rows','cols','accept','action','method','for',
     'list','label','datetime','cite','lang','dir','role','srcset','media',
     'sizes','loading','controls','poster','loop','muted','autoplay',
     'preload','playsinline','kind','srclang','default','open','download',
     'hidden','contenteditable',
+    // Bug fix: <select size="4">/<input size> and <meter low/high/optimum>
+    // were still being stripped even though <select>/<meter> are already in
+    // ALLOWED_TAGS -- only these four attribute names were missing here.
+    // Effect: a multi-select rendered at default height instead of the
+    // requested row count, and <meter> lost its threshold-based gauge
+    // colouring. Pure presentation/semantic attributes -- no URL, no
+    // script, no event-handler surface -- so no security weight added.
+    'low','high','optimum',
     // SVG presentation attributes (explicit route -- see ALLOWED_TAGS
     // comment on the SVG tag list). Covers the fixture's <svg viewBox
     // role>/<rect>/<circle>/<text> block plus the common presentation