docs: update README performance section with current benchmarks

Replace old performance table with comprehensive benchmarks across
four categories: working tree ops (vs native git), bare repo ops,
Linux kernel scale test, and HTTP clone. PureGit handler-level
performance now beats native git on most operations.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: Lukáš Kříž

README.md

@@ -209,20 +209,45 @@ Acceptance tests run automatically in GitHub Actions CI after the QA pipeline pa
 
 ## Performance
 
+Optimized for real-world working tree operations. PureGit's core algorithms are competitive with — and in many cases faster than — native git, with the CLI overhead dominated by PHP interpreter startup (~52 ms fixed cost).
+
 Delta encoding with sliding window (window=10, max depth=50) achieves ~77% compression ratio on similar objects. Packs use OFS_DELTA format. Transport streams packs directly to disk with a bounded FIFO cache (32 MB) for index building, keeping memory usage predictable regardless of repository size.
 
-### Local operations
+### Working tree operations
+
+Benchmarked on a real-world PHP project (1 056 files, 21 gitignore rules):
+
+| Operation | PureGit | Native git | |
+|---|---|---|---|
+| `status` | 12 ms | 19 ms | 1.5x faster |
+| `diff` | 6 ms | 13 ms | 2.2x faster |
+| `diff --cached` | 3 ms | 12 ms | 4.6x faster |
+| `log -10` | < 0.1 ms | 11 ms | > 100x faster |
+| `show HEAD` | < 0.1 ms | 12 ms | > 100x faster |
+
+PureGit times are handler-level (warm cache). Native git times are `exec()`-based (include ~12 ms process startup). CLI wall-clock adds ~52 ms PHP interpreter startup on top.
+
+### Bare repository operations
+
+Benchmarked against PHPUnit bare repository (231 MB, 27k commits, 3 576 files):
+
+| Operation | PureGit | Native git | |
+|---|---|---|---|
+| Resolve HEAD | 0.1 ms | 12 ms | 120x faster |
+| List all refs (995) | 0.2 ms | 15 ms | 65x faster |
+| Log 100 commits | 3 ms | 15 ms | 4x faster |
+| Walk HEAD tree (3 576 files) | 8 ms | 16 ms | 2x faster |
+| Log 1 000 commits | 27 ms | 22 ms | 1.2x slower |
+| Count all commits (BFS) | 289 ms | 128 ms | 2.2x slower |
+| Count all commits (commit-graph) | 2 ms | 119 ms | 60x faster |
 
-Benchmarked against PHPUnit bare repository (231 MB, 27k commits, 3576 files):
+### Scale: Linux kernel (6.1 GB, 1.4M commits)
 
-| Operation | Time | Peak Memory |
-|---|---|---|
-| Read HEAD commit | 25 ms | 34 MB |
-| Walk 3576 files | 10 ms | 34 MB |
-| Log 1000 commits | 13 ms | 34 MB |
-| Read all blobs | 235 ms | 92 MB |
-| Count all commits (commit-graph) | 2 ms | 36 MB |
-| Count all commits (BFS) | 283 ms | 62 MB |
+| Operation | PureGit | Native git | |
+|---|---|---|---|
+| Count all commits (BFS) | 27 s | 8 s | 3.4x slower |
+| Count all commits (commit-graph) | 109 ms | — | — |
+| Peak memory (BFS) | 2 087 MB | — | — |
 
 ### Clone (HTTP transport)