.btn font-family: explicit Segoe UI / system-ui stack — kills the Firefox UA-default inheritance trap

User reported the Firefox inspector "consistently said Georgia but renders sans-serif" on .btn-primary buttons (CONT GAME, OK, etc.). Root cause: Firefox's UA stylesheet sets a hard font-family on `<button>` elements that overrides any inherited body font, but the inspector's computed-style panel reports the inherited value (Georgia from `body`) and silently masks the UA override. On Windows that UA default is Segoe UI — which the user had grown accustomed to.

Fix: explicit `font-family: "Segoe UI", system-ui, sans-serif;` on `.btn` in `_button-pad.scss:11`. Three benefits:
- Inspector + render now agree (no more "lies about Georgia").
- Cross-OS uniformity: Windows → Segoe UI, macOS w. Office → Segoe UI, otherwise system-ui → San Francisco, Linux → OS UI font, last-ditch sans-serif.
- Kills the `<a class="btn">` vs `<button class="btn">` typeface split flagged in [[feedback-btn-vs-anchor-font-family]] (anchors used to render serif via inheritance, buttons sans-serif via UA default — both now render Segoe regardless of element).

Memory update: `feedback_btn_vs_anchor_font_family.md` rewritten — the "prefer <button> over <a> for typeface consistency" rule is OBSOLETE; element choice is now purely semantic (button for actions, anchor for navigation, form for POSTs). The iter-6b form-wrap SCSS-pin trap stays valid + carries over.

No tests needed — pure visual / cross-OS rendering change.

Code architected by Disco DeDisco <discodedisco@outlook.com>
Git commit message Co-Authored-By:
Claude Sonnet 4.6 <noreply@anthropic.com>

src/static_src/scss/_button-pad.scss

@@ -8,7 +8,7 @@
     text-shadow: 0 0 0.25rem rgba(0, 0, 0, 0.5);
     border: 0.15rem solid rgba(var(--priUser), 1);
     border-radius: 50%;
-    font-family: 'Arial', sans-serif;
+    font-family: 'Segoe UI', system-ui, sans-serif;
     font-weight: 700;
     font-size: 0.63rem;
     text-transform: uppercase;