iris: make font families application-named strings

docs/PLAN.md

@@ -813,12 +813,14 @@ widget changed. Winit's user-event proxy and Android's posted callback are
 private implementations of that wake; applications do not define platform
 event types or manually request redraws.
 
-**Iris ships no fonts.** Applications register their own font bytes on `Ui`
-before the first text shape and select them through the same `Family` used by
-text widgets. `Family::Icons` is a semantic application-configured role, not a
-particular icon set owned by the framework. ai-app owns its Nerd Fonts subset,
-its codepoints, its license and the script that rebuilds it; body and monospace
-families continue to come from the platform.
+**Iris ships no fonts, and font families are application-named strings**
+(2026-09-12). Applications register their own font bytes on `Ui` before the
+first text shape and select them by the same string used by text widgets. The
+public boundaries accept `AsRef<str>`, so an application can use bare strings
+or put its own semantic enum in front of them without Iris hardcoding the
+roles. ai-app owns the `ai-app-icons` family, its Nerd Fonts subset, its
+codepoints, its license and the script that rebuilds it; the CSS generic names
+`sans-serif` and `monospace` continue to resolve through the platform.
 
 `cargo-iris` is an installable Cargo subcommand, rather than a script callers
 must find inside an Iris checkout. `cargo iris apk` builds the Rust `cdylib`