docs(docs): add new problem documentation pages and source selector component

apps/docs/content/(01-linear-structures)/stack/224_basic-calculator.mdx

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+---
+title: '224. Basic Calculator'
+description: Given a string s representing a valid expression, implement a basic calculator to evaluate it, and return the result of the evaluation
+icon: dot
+topics:
+  - { name: "Math", slug: "math" }
+  - { name: "String", slug: "string" }
+  - { name: "Stack", slug: "stack" }
+  - { name: "Recursion", slug: "recursion" }
+issue: "https://github.com/prdlk/leetcode/issues/71"
+sidebar:
+  label: 'Basic Calculator'
+  badge: 'Hard'
+---
+
+### Example 1:
+- Input: `s = "1 + 1"`
+- Output: `2`
+
+### Example 2:
+- Input: `s = " 2-1 + 2 "`
+- Output: `3`
+
+### Example 3:
+- Input: `s = "(1+(4+5+2)-3)+(6+8)"`
+- Output: `23`
+
+### Constraints:
+
+- `1 <= s.length <= 3 * 10^5`
+- `s` consists of digits, '+', '-', '(', ')', and ' '.
+- `s` represents a valid expression.
+- '+' is not used as a unary operation (i.e., "+1" and "+(2 + 3)" is invalid).
+- '-' could be used as a unary operation (i.e., "-1" and "-(2 + 3)" is valid).
+- There will be no two consecutive operators in the input.
+- Every number and running calculation will fit in a signed 32-bit integer.
+
+## Solution
+
+```py
+class Solution:
+    def calculate(self, s: str) -> int:
+```