iris: share resource handle bookkeeping

docs/PLAN.md

@@ -818,14 +818,17 @@ event types or manually request redraws.
 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. Text buffers, layouts,
-and prepared glyphs live in a per-`Ui` generational arena; a text widget holds
-one compact handle into it, while the arena and its shaping state are shared by
-one `Rc<RefCell<_>>`. Registering another family invalidates the live arena
-entries and dirties their active owner widgets, so registration is also valid
-after the first shape. 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.
+and prepared glyphs live in a per-`Ui` `Resources<TextRsc>` generational arena;
+a text widget's `TextHandle` wraps the UI-local `RscHandle` into it. The same
+generic arena owns texture and managed-paint lifetimes. Its `StrongRscId` and
+`WeakRscId` are sendable IDs rather than data pointers; clone and drop events
+cross one arena-owned standard channel, and reference counts remain in the
+arena instead of allocating one atomic counter per resource. Registering
+another family invalidates the live text entries and dirties their active owner
+widgets, so registration is also valid after the first shape. 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`