fix(waybar): stop summer themes rendering phantom workspaces

summer-day/summer-night showed all 10 workspace icons up-front. The cause:
legacy used the deprecated `persistent_workspaces` (underscore), which
current Waybar silently ignores — so legacy only ever showed *existing*
workspaces. The v1 port rewrote it to the modern `persistent-workspaces`
(hyphen), which Waybar honours, surfacing all ten as phantoms.

Drop the block from both summer waybar.jsonc whole-swaps. The other themes
render from waybar.nix, which never declared persistent-workspaces, so they
already only show existing workspaces — no change needed there.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

README.md

@@ -386,8 +386,10 @@ close · `SUPER+1..9` workspaces · `Print` region screenshot.
   field (`{active, inactive}`) to the theme schema (`theme.nix`), consumed
   solid in `hyprland.nix`, and declared it in every preset so a switch
   always replaces it. All six identity themes now match legacy exactly.
-- **Waybar shows non-existent workspaces:** in summer-night/summer-day the
-  bar renders every workspace icon up-front via `persistent-workspaces` /
-  `all-outputs` in `themes/summer-{day,night}/waybar.jsonc`. Restore the
-  legacy behaviour (only show workspaces that exist) here and across the
-  other themes.
+- ✓ **Waybar shows non-existent workspaces:** the v1 summer port "fixed"
+  legacy's deprecated `persistent_workspaces` (underscore — silently
+  ignored by current Waybar, so legacy only ever showed existing
+  workspaces) into the modern `persistent-workspaces` (hyphen), which
+  Waybar honours → all 10 rendered as phantoms. Dropped the block from
+  `themes/summer-{day,night}/waybar.jsonc`; the other themes use the
+  generated `waybar.nix`, which never had it, so they already match.