feat(leetcode): add tries, segment tree, and fenwick tree roadmaps

[royalknight71]

Description

As requested in issue #9902, this PR significantly expands the LeetCode/Competitive Programming roadmap by adding modular nodes and comprehensive educational learning resources for advanced data structures.

Changes Made

• Added a roadmap node for Tries (Prefix Trees) including core theory and Striver's A2Z implementation links.
• Added a roadmap node for Segment Trees detailing range queries and lazy propagation mechanisms.
• Added a roadmap node for Fenwick Trees (Binary Indexed Trees) highlighting bitwise operations for prefix calculations.

Closes #9902

[jcanalesluna]

Hi, thanks for the PR. I'm not going to merge it because this would break the format and consistency of the roadmap. As you can see, every spine node here comes with its own row of problem-siblings. A bare "Segment Trees" box with no problem cluster next to it would visually stick out. I've instead added the resource of Segment Trees and Fenwick Trees in the Trees node.