docs(content): add issue URLs to problem pages and restructure guides into appendix

apps/docs/content/(04-relational)/graph-bfs/127-word-ladder.mdx

@@ -7,6 +7,7 @@ topics:
   - { name: "String", slug: "string" }
   - { name: "Breadth-First Search", slug: "breadth-first-search" }
   - { name: "Bidirectional Search", slug: "bidirectional-search" }
+issue: "https://github.com/prdlk/leetcode/issues/138"
 sidebar:
   label: 'Word Ladder'
   badge: 'Hard'

apps/docs/content/(04-relational)/graph-bfs/994-rotting-oranges.mdx

@@ -6,6 +6,7 @@ topics:
   - { name: "Array", slug: "array" }
   - { name: "Breadth-First Search", slug: "breadth-first-search" }
   - { name: "Matrix", slug: "matrix" }
+issue: "https://github.com/prdlk/leetcode/issues/137"
 sidebar:
   label: 'Rotting Oranges'
   badge: 'Medium'

apps/docs/content/(04-relational)/graph-dfs/133-clone-graph.mdx

@@ -7,6 +7,7 @@ topics:
   - { name: "Depth-First Search", slug: "depth-first-search" }
   - { name: "Breadth-First Search", slug: "breadth-first-search" }
   - { name: "Graph Theory", slug: "graph" }
+issue: "https://github.com/prdlk/leetcode/issues/131"
 sidebar:
   label: 'Clone Graph'
   badge: 'Medium'

apps/docs/content/(04-relational)/graph-dfs/200-number-of-islands.mdx

@@ -8,6 +8,7 @@ topics:
   - { name: "Breadth-First Search", slug: "breadth-first-search" }
   - { name: "Union-Find", slug: "union-find" }
   - { name: "Matrix", slug: "matrix" }
+issue: "https://github.com/prdlk/leetcode/issues/130"
 sidebar:
   label: 'Number of Islands'
   badge: 'Medium'

apps/docs/content/(04-relational)/graph-dfs/417-pacific-atlantic-water-flow.mdx

@@ -7,6 +7,7 @@ topics:
   - { name: "Depth-First Search", slug: "depth-first-search" }
   - { name: "Breadth-First Search", slug: "breadth-first-search" }
   - { name: "Matrix", slug: "matrix" }
+issue: "https://github.com/prdlk/leetcode/issues/132"
 sidebar:
   label: 'Pacific Atlantic Water Flow'
   badge: 'Medium'

apps/docs/content/(04-relational)/topological-sort/207-course-schedule.mdx

@@ -8,6 +8,7 @@ topics:
   - { name: "Graph Theory", slug: "graph" }
   - { name: "Topological Sort", slug: "topological-sort" }
   - { name: "Directed Acyclic Graph", slug: "directed-acyclic-graph" }
+issue: "https://github.com/prdlk/leetcode/issues/142"
 sidebar:
   label: 'Course Schedule'
   badge: 'Medium'

apps/docs/content/(04-relational)/topological-sort/210-course-schedule-ii.mdx

@@ -7,6 +7,7 @@ topics:
   - { name: "Breadth-First Search", slug: "breadth-first-search" }
   - { name: "Graph Theory", slug: "graph" }
   - { name: "Topological Sort", slug: "topological-sort" }
+issue: "https://github.com/prdlk/leetcode/issues/143"
 sidebar:
   label: 'Course Schedule II'
   badge: 'Medium'

apps/docs/content/(04-relational)/union-find/323-number-of-connected-components-in-an-undirected-graph.mdx

@@ -7,6 +7,7 @@ topics:
   - { name: "Breadth-First Search", slug: "breadth-first-search" }
   - { name: "Union-Find", slug: "union-find" }
   - { name: "Graph Theory", slug: "graph" }
+issue: "https://github.com/prdlk/leetcode/issues/147"
 sidebar:
   label: 'Number of Connected Components in an Undirected Graph'
   badge: 'Medium'

apps/docs/content/(04-relational)/union-find/684-redundant-connection.mdx

@@ -7,6 +7,7 @@ topics:
   - { name: "Breadth-First Search", slug: "breadth-first-search" }
   - { name: "Union-Find", slug: "union-find" }
   - { name: "Graph Theory", slug: "graph" }
+issue: "https://github.com/prdlk/leetcode/issues/146"
 sidebar:
   label: 'Redundant Connection'
   badge: 'Medium'