Label text stages in the chain list with their words

Effect::label(values) names a stage in a list, defaulting to the title;
the text effect answers "Text (words)", and the chain rows are renamed
in place as params change.

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

src/effects/text.cpp

@@ -203,6 +203,22 @@ void TextEffect::loadBoxImage(const std::string& path, Image& image,
     alpha = cachedAlpha_;
 }
 
+std::string TextEffect::label(const ParamValues& values) const {
+    // Several lines read as one: each run of whitespace becomes a single space.
+    std::string words;
+    bool gap = false;
+    for (const char c : paramText(values, "text", "")) {
+        if (c == ' ' || c == '\t' || c == '\n' || c == '\r') {
+            gap = !words.empty();
+            continue;
+        }
+        if (gap) words += ' ';
+        gap = false;
+        words += c;
+    }
+    return words.empty() ? title() : title() + " (" + words + ")";
+}
+
 Image TextEffect::render(const std::vector<Image>& sources, int width, int height, Rng& rng,
                          const ParamValues& values) const {
     if (width < 1 || height < 1) throw EffectError("Canvas size must be at least 1x1 pixels.");

src/effects/text.hpp

@@ -30,6 +30,8 @@ public:
     const std::vector<ParamSpec>& params() const override;
     std::string styleKind() const override { return "text"; }
     bool needsSources() const override { return false; }
+    // "Text (Hello world)", so stages writing different words tell apart.
+    std::string label(const ParamValues& values) const override;
 
     Image render(const std::vector<Image>& sources, int width, int height, Rng& rng,
                  const ParamValues& values) const override;