Implement the reviewed UI icon system and durable review workflow (#853)

Thanks @Nathan-Dane.

docs/ui-icon-inventory.md

@@ -0,0 +1,22 @@
+# UI icon maintenance
+
+The authoritative authoring specification is
+[assets/icons/ui/STYLE_GUIDE.md](../assets/icons/ui/STYLE_GUIDE.md), with mandatory
+agent instructions beside it. Start at
+[the UI icon README](../assets/icons/ui/README.md) for the included review app,
+canonical resource paths, new-icon scaffold, exports and checks.
+
+Launch the repository-owned review tool with:
+
+```sh
+python3 -B assets/icons/ui/design/tools/icon_status.py --serve
+```
+
+Open http://127.0.0.1:8770/. Every discovered icon without a current acceptance is
+Open. SVGs, aliases and source references are scanned automatically; unused masters
+are included. Counts and CSV reports are derived at runtime, not maintained here.
+`--csv` writes `target/icon-inventory.csv`.
+
+The design and cleanup plan is [ui-icon-maintenance-plan.md](ui-icon-maintenance-plan.md).
+The old proposal is superseded. SVG masters, palette, aliases, the original Rust
+viewport glyphs and owner review records remain the application resources.