docs(docs): replace Mermaid diagram with SVG image for dependency spine

README.md

@@ -321,27 +321,8 @@
   </tbody>
 </table>
 
-## Dependency Spine (Mermaid)
+## Dependency Spine
 
-```mermaid
+<p align="center">
-graph LR
+  <img alt="Dependency graph of the 24 topics across five phases, showing which topics build on which" src=".github/assets/dependency-spine.svg" />
-  T1["1 Hash"] --> T2["2 Prefix Sum"]
+</p>
-  T3["3 Two Pointers"] --> T4["4 Sliding Window"]
-  T4 --> T10["10 Matrix Index Math"]
-  T5["5 Binary Search"] --> T13["13 BST"]
-  T6["6 Stack"] --> T7["7 Monotonic Stack"]
-  T8["8 Linked List"] --> T9["9 Hybrid"]
-  T1 --> T9
-  T11["11 Tree DFS"] --> T13
-  T11 --> T14["14 Heap"]
-  T11 --> T15["15 Trie"]
-  T11 --> T16["16 Graph DFS"]
-  T12["12 Tree BFS"] --> T17["17 Graph BFS"]
-  T16 --> T18["18 Topological Sort"]
-  T16 --> T19["19 Union-Find"]
-  T18 --> T20["20 Backtracking"]
-  T20 --> T21["21 DP 1-D"]
-  T21 --> T22["22 DP Multi-D"]
-  T21 --> T23["23 Greedy"]
-  T23 --> T24["24 Intervals"]
-```