docs(docs): add ProblemBadges component, layout slot, and enrich pages with topics/video frontmatter, plus guide placeholders and topic‑landing map.

apps/docs/content/(02-nodal-grid)/matrix-index-math/54-spiral-matrix.mdx

@@ -2,13 +2,16 @@
 title: '54. Spiral Matrix'
 description: Given an m x n matrix, return all elements of the matrix in spiral order
 icon: dot
+topics:
+  - { name: "Array", slug: "array" }
+  - { name: "Matrix", slug: "matrix" }
+  - { name: "Simulation", slug: "simulation" }
+video: "BJnMZNwUk1M"
 sidebar:
   label: 'Spiral Matrix'
   badge: 'Medium'
 ---
 
-<Badge variant="accent">Array</Badge>
-
 ### Example 1:
 - Input: `matrix = [[1,2,3],[4,5,6],[7,8,9]]`
 - Output: `[1,2,3,6,9,8,7,4,5]`
@@ -76,7 +79,3 @@ class Solution:
 
         return res
 ```
-
-## Explanation
-
-<YouTube id="BJnMZNwUk1M" title="Spiral Matrix - Microsoft Interview Question - Leetcode 54" />