fix(demo): force en-US locale on R1CS constraint count + refresh evidence

End-to-end test pass on this commit produced two cosmetic + content
updates:

  1. Constraint count rendered as "1.026" on locales that pick a
     European thousands separator. Three call sites of
     `Number.toLocaleString()` without an explicit locale arg were
     hardcoded to en-US via the existing `formatNumber` helper:
       - aside heading ("1,026 R1CS constraints")
       - table footer total
       - PLONK comparison's Groth16 circuit row
     Confirmed in the live preview: all three now read "1,026".

  2. evidence.json regenerated by re-running the generator binary.
     The numbers stayed reproducible (same setup/prove seeds, same
     SHA-256 digests of the .bin artifacts); only the wall-clock
     timing fields drifted by 1-3 ms (setup 80→83 ms) and the
     `generated_at` timestamp moved forward. Re-shipping the fresh
     evidence so the demo's "Captured at" line matches the live commit.

End-to-end test recap before this fix:

  ✓ 5/5 mosaic-demo-sudoku unit tests pass
  ✓ generate-fixtures runs clean: arkworks accept, Mosaic accept,
    tampered reject (PointNotOnCurve), PLONK accept (2 ms via
    mosaic-plonk on the snarkjs 0.7.6 mul-circuit fixture)
  ✓ pnpm next build clean: /demo/sudoku route 12.6 kB / 162 kB FLJ
  ✓ Browser preview exercise:
    - 81 cells, 21 clue cells highlighted
    - Hero mark = /assets/mosaic.webp (Mosaic mark, not Wiener)
    - Hover center cell (idx 40) → 1 focused + 20 in-group cells
      (8 row + 8 col + 4 box-non-overlap), readout shows the
      coordinate + role + value + in-circuit work breakdown
    - "Reveal solution" toggle: 21 → 81 filled, back to 21 on undo
    - Proof anatomy: 8 chunks rendered with real hex from
      proof_valid.bin, click chunk #3 (B.x.c0) → detail card shows
      "G2 affine x (Fq2 real)" with ADR-0003 Fq2 ordering note
    - Verify tabs swap correctly; tampered tab activates as
      "Verify tampered proof"
    - PLONK comparison panel: 2 columns populated, second heading
      "KZG-PLONK · BN254", both digest links present
    - 2 terminals on page (verify panel + page-07 runtime evidence)

Author: kh0ra

site/app/demo/sudoku/SudokuDemo.tsx

@@ -561,7 +561,7 @@ export function SudokuDemo() {
           <header className="demo-aside-header">
             <span className="tag">CIRCUIT</span>
             <h2 className="sub-display">
-              {evidence.constraint_count.toLocaleString()} R1CS constraints
+              {formatNumber(evidence.constraint_count)} R1CS constraints
             </h2>
           </header>
           <table className="demo-table">
@@ -582,7 +582,7 @@ export function SudokuDemo() {
               ))}
               <tr className="demo-table-total">
                 <td colSpan={2}>Total</td>
-                <td className="demo-table-num">{cb.total.toLocaleString()}</td>
+                <td className="demo-table-num">{formatNumber(cb.total)}</td>
               </tr>
             </tbody>
           </table>
@@ -847,7 +847,7 @@ export function SudokuDemo() {
                 <div>
                   <dt>Circuit</dt>
                   <dd>
-                    Sudoku 9×9, {evidence.constraint_count.toLocaleString()} R1CS, {evidence.public_input_count}{" "}
+                    Sudoku 9×9, {formatNumber(evidence.constraint_count)} R1CS, {evidence.public_input_count}{" "}
                     public inputs
                   </dd>
                 </div>

site/public/demo/sudoku/evidence.json

@@ -1,8 +1,8 @@
 {
   "schema_version": 1,
-  "generated_at": "2026-05-11T19:10:12Z",
+  "generated_at": "2026-05-11T19:20:06Z",
   "workspace_version": "0.9.15-onchain-compressed-verify",
-  "repo_commit_sha": "473841b",
+  "repo_commit_sha": "ea5353b",
   "puzzle_source": "Inkala 2010 (21-clue hardest-class)",
   "puzzle": [
     8,
@@ -186,7 +186,7 @@
   "setup_seed": "0xc0ffeedead42beef",
   "prove_seed": "0xb16b00b5deadc0de",
   "timings": {
-    "setup_ms": 77,
+    "setup_ms": 83,
     "prove_ms": 22,
     "verify_arkworks_ms": 1,
     "verify_mosaic_valid_ms": 2,