doc: Add titles to plots, fix plot location

benchmarks/README.md

@@ -22,7 +22,7 @@ Quality and speed across all methods.
 | BM25 | 0.673 | 263 ms | 0.02 ms |
 | ripgrep | 0.126 | — | 12 ms |
 
-| ![Speed vs quality (cold)](results/speed_vs_ndcg_cold.png) | ![Speed vs quality (warm)](results/speed_vs_ndcg_warm.png) |
+| ![Speed vs quality (cold)](../assets/images/speed_vs_ndcg_cold.png) | ![Speed vs quality (warm)](../assets/images/speed_vs_ndcg_warm.png) |
 |:--:|:--:|
 | *Time to first result (index + query) vs NDCG@10* | *Query latency on a warm index vs NDCG@10* |
 
@@ -197,6 +197,6 @@ uv run python -m benchmarks.baselines.coderankembed --mode semantic
 uv run python -m benchmarks.plot
 ```
 
-Writes `speed_vs_ndcg_cold.png` and `speed_vs_ndcg_warm.png` to `benchmarks/results/`.
+Writes `speed_vs_ndcg_cold.png` and `speed_vs_ndcg_warm.png` to `assets/images/`.
 
 </details>

benchmarks/plot.py

@@ -110,7 +110,8 @@ def _format_ms(v: float, _: object) -> str:
 
 
 def _make_plot(out_path: Path, *, warm: bool = False) -> None:
-    """Generate a speed-vs-quality scatter plot.
+    """
+    Generate a speed-vs-quality scatter plot.
 
     :param out_path: Destination PNG path.
     :param warm: If True, use per-query latency (index pre-built). If False, use index + query latency.
@@ -176,14 +177,15 @@ def _make_plot(out_path: Path, *, warm: bool = False) -> None:
     ax.set_ylabel("NDCG@10", fontsize=10, color="#444444")
     ax.set_ylim(0.05, 0.95)
 
+    ax.set_xlabel("Query latency", fontsize=10, color="#444444")
     if warm:
-        ax.set_xlabel("Query latency (warm)", fontsize=10, color="#444444")
         ax.set_xlim(0.01, 500)
         ax.set_xticks([0.1, 1, 10, 100])
+        ax.set_title("Code search quality vs. latency (warm)", fontsize=12, color="#222222", pad=12)
     else:
-        ax.set_xlabel("Query latency (cold)", fontsize=10, color="#444444")
         ax.set_xlim(5, 200_000)
         ax.set_xticks([100, 1_000, 10_000, 100_000])
+        ax.set_title("Code search quality vs. latency (cold)", fontsize=12, color="#222222", pad=12)
 
     ax.xaxis.set_major_formatter(ticker.FuncFormatter(_format_ms))
     ax.tick_params(labelsize=9, colors="#555555")