README: 308 effects, and a test keeps the count current (#2565)

The README quoted 306 effects in three places while the registry (and the
generated docs/effects.md) had 307, now 308. A catalog test checks every
effect count the README gives against the registry.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

README.md

@@ -20,7 +20,7 @@
 
 <p align="center">
   A free, open-source compositor: compositions, layers,
-  keyframes, 306 effects, layer styles, expressions, 3D cameras and lights, and a render queue, native on macOS,
+  keyframes, 308 effects, layer styles, expressions, 3D cameras and lights, and a render queue, native on macOS,
   Windows and Linux, and in the browser. Young, moving fast, and already usable.
 </p>
 
@@ -127,7 +127,7 @@ or into the Timeline, between layers and at the time you point to.
 
 ## Effects
 
-306 built-in effects across its categories, each with its parameter names, order and
+308 built-in effects across its categories, each with its parameter names, order and
 defaults: blur and sharpen, channel, color correction (Curves, Levels, Hue/Saturation, a full
 color-grading panel…), distort (Warp, Bulge, Turbulent Displace, CC Power Pin…), generate (Fractal Noise,
 Gradient Ramp, Stroke, Write-on, Audio Spectrum…), keying, matte, noise and grain, perspective,
@@ -231,7 +231,7 @@ tests, layering, asset attribution and the WebAssembly build). See [CONTRIBUTING
 ## Where it stands
 
 EffectCraft is young: its first commit was on 1 October 2026. A comprehensive feature set
-exists, including 306 effects, but breadth is not the same as full maturity across every edge
+exists, including 308 effects, but breadth is not the same as full maturity across every edge
 case. Today it's a good place to try things and to tell us what breaks. It isn't yet recommended
 for production client work. In particular:
 

crates/effects/src/catalog.rs

@@ -182,6 +182,20 @@ mod tests {
         assert!(have == want, "docs/effects.md is stale: UPDATE_DOCS=1 cargo test -p effectcraft-effects --lib effects_doc_is_current");
     }
 
+    /// The README quotes the number of effects (#2565): every count it gives is the registry's.
+    #[test]
+    fn readme_effect_counts_are_current() {
+        let readme = std::fs::read_to_string(concat!(env!("CARGO_MANIFEST_DIR"), "/../../README.md")).unwrap_or_default();
+        let words: Vec<&str> = readme.split_whitespace().collect();
+        let counts: Vec<&str> = words
+            .windows(3)
+            .filter(|w| w[0].parse::<u32>().is_ok() && (w[1].starts_with("effects") || (w[1] == "built-in" && w[2].starts_with("effects"))))
+            .map(|w| w[0])
+            .collect();
+        let n = super::registry().len().to_string();
+        assert!(!counts.is_empty() && counts.iter().all(|c| *c == n), "README.md says {counts:?} effects; the registry has {n}");
+    }
+
     #[test]
     fn cpu_only_controls_keep_effects_off_the_gpu() {
         use effectcraft_keyframe::Value;