feat(icons): add scan-square (#4550)

* feat(icons): add scan-square

Adds scan-square: a scanning frame with a square detected inside it.

The scan-* family covers what is being detected — scan-face, scan-heart,
scan-text, scan-eye, scan-barcode, scan-qr-code, scan-search, scan-line —
but has nothing for a plain shape or object.

Composed entirely from two existing icons rather than new geometry: the
four corner brackets are scan's, verbatim, and the inner block is
square-square's rect(8,8,8,8) rx=1, verbatim. Nothing here is drawn from
scratch, so it sits in the family without introducing a new vocabulary.

* chore(icons): fill scan-square use-cases and fix recognise/recognize tags

Addresses review on #4550: fills the use-cases field per @ericfennis, and
collapses the duplicate recognise/recognize tags into a single
recognition tag, matching scan-text's vocabulary per @Copilot.

* Update icons/scan-square.json

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

* Update icons/scan-square.json

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

---------

Co-authored-by: Eric Fennis <eric.fennis@gmail.com>
Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>
Co-authored-by: Karsa <contact@karsa.org>

icons/scan-square.json

@@ -0,0 +1,39 @@
+{
+  "$schema": "../icon.schema.json",
+  "contributors": [
+    "samuelalake"
+  ],
+  "use-cases": [
+    "detecting or selecting a shape or object inside a camera or AR viewfinder",
+    "a 'select shape' or region-detection control in a design or image editor",
+    "indicating camera scan mode or live scanning area",
+    "marking the crop area for creating square thumbnails",
+    "representing a region-of-interest for OCR or barcode capture",
+    "visualizing detected objects in an augmented reality overlay",
+    "toggling a scanning control in a camera or scanner app"
+  ],
+  "tags": [
+    "scan",
+    "square",
+    "detect",
+    "recognition",
+    "select",
+    "frame",
+    "object",
+    "viewfinder",
+    "capture",
+    "shape",
+    "boundary",
+    "camera",
+    "scanner",
+    "overlay",
+    "focus",
+    "crop",
+    "marker"
+  ],
+  "categories": [
+    "photography",
+    "design",
+    "development"
+  ]
+}

icons/scan-square.svg

@@ -0,0 +1,17 @@
+<svg
+  xmlns="http://www.w3.org/2000/svg"
+  width="24"
+  height="24"
+  viewBox="0 0 24 24"
+  fill="none"
+  stroke="currentColor"
+  stroke-width="2"
+  stroke-linecap="round"
+  stroke-linejoin="round"
+>
+  <path d="M3 7V5a2 2 0 0 1 2-2h2" />
+  <path d="M17 3h2a2 2 0 0 1 2 2v2" />
+  <path d="M21 17v2a2 2 0 0 1-2 2h-2" />
+  <path d="M7 21H5a2 2 0 0 1-2-2v-2" />
+  <rect width="8" height="8" x="8" y="8" rx="1" />
+</svg>