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

apps/docs/content/(01-linear-structures)/two-pointers/11-container-with-most-water.mdx

@@ -7,6 +7,7 @@ topics:
   - { name: "Two Pointers", slug: "two-pointers" }
   - { name: "Greedy", slug: "greedy" }
 video: "UuiTKBwPgAo"
+issue: "https://github.com/prdlk/leetcode/issues/44"
 sidebar:
   label: 'Container With Most Water'
   badge: 'Medium'

apps/docs/content/(01-linear-structures)/two-pointers/125-valid-palindrome.mdx

@@ -6,6 +6,7 @@ topics:
   - { name: "Two Pointers", slug: "two-pointers" }
   - { name: "String", slug: "string" }
 video: "jJXJ16kPFWg"
+issue: "https://github.com/prdlk/leetcode/issues/41"
 sidebar:
   label: 'Valid Palindrome'
   badge: 'Easy'

apps/docs/content/(01-linear-structures)/two-pointers/15-3sum.mdx

@@ -7,6 +7,7 @@ topics:
   - { name: "Two Pointers", slug: "two-pointers" }
   - { name: "Sorting", slug: "sorting" }
 video: "jzZsG8n2R9A"
+issue: "https://github.com/prdlk/leetcode/issues/43"
 sidebar:
   label: '3Sum'
   badge: 'Medium'

apps/docs/content/(01-linear-structures)/two-pointers/167-two-sum-ii-input-array-is-sorted.mdx

@@ -7,6 +7,7 @@ topics:
   - { name: "Two Pointers", slug: "two-pointers" }
   - { name: "Binary Search", slug: "binary-search" }
 video: "cQ1Oz4ckceM"
+issue: "https://github.com/prdlk/leetcode/issues/42"
 sidebar:
   label: 'Two Sum II - Input Array Is Sorted'
   badge: 'Medium'

apps/docs/content/(01-linear-structures)/two-pointers/392-is-subsequence.mdx

@@ -7,6 +7,7 @@ topics:
   - { name: "String", slug: "string" }
   - { name: "Dynamic Programming", slug: "dynamic-programming" }
 video: "99RVfqklbCE"
+issue: "https://github.com/prdlk/leetcode/issues/45"
 sidebar:
   label: 'Is Subsequence'
   badge: 'Easy'

apps/docs/content/(01-linear-structures)/two-pointers/977-squares-of-a-sorted-array.mdx

@@ -7,6 +7,7 @@ topics:
   - { name: "Two Pointers", slug: "two-pointers" }
   - { name: "Sorting", slug: "sorting" }
 video: "FPCZsG_AkUg"
+issue: "https://github.com/prdlk/leetcode/issues/46"
 sidebar:
   label: 'Squares of a Sorted Array'
   badge: 'Easy'