Drop the daytime widget, use clock everywhere

Clock and daytime were near-duplicates with different click semantics
(clock toggles between formats on left-click and opens the timezone
selector on right-click; daytime was non-pressable with a hover tooltip).
Standardize on clock, since it's the more capable of the two.

- Delete widgets/daytime.qml and its FirstPartyWidgets entry.
- Migrate shell-defaults.json, shell.qml's builtin fallback, Bar.qml's
  fallback bar config, and the settings panel's builtin defaults so the
  center anchor and center-section entry both reference "clock".
- Rename the daytimeSettings form to clockSettings and rephrase
  "Tooltip format" → "Alternate format (click to toggle)" so the field
  label matches clock's actual behavior.
- Update the gallery dropdown options and bar/README docs.

shell/plugins/bar/README.md

@@ -16,7 +16,7 @@ the shell for its whole session.
 
 The bar config lives under the `bar:` key of [`~/.config/omarchy/shell.json`](../../README.md#shelljson-shape). Out of the box the shell uses [`shell-defaults.json`](../../shell-defaults.json). Once you customize anything via `omarchy launch bar settings` or by editing shell.json directly, your file is canonical — there is no deep-merge.
 
-Launch the visual editor with `omarchy launch bar settings` (or run `omarchy-launch-bar-settings`) to reorder widgets, add/remove them, and tweak per-widget options without editing JSON by hand. You can also right-click empty space to the left or right of the centered daytime module to open it; double-left-click the same empty space to toggle bar transparency.
+Launch the visual editor with `omarchy launch bar settings` (or run `omarchy-launch-bar-settings`) to reorder widgets, add/remove them, and tweak per-widget options without editing JSON by hand. You can also right-click empty space to the left or right of the centered clock module to open it; double-left-click the same empty space to toggle bar transparency.
 
 Example `shell.json` (bar subtree only shown):
 
@@ -26,7 +26,7 @@ Example `shell.json` (bar subtree only shown):
   "bar": {
     "position": "top",
     "transparent": false,
-    "centerAnchor": "daytime",
+    "centerAnchor": "clock",
     "layout": {
       "left": [
         { "id": "omarchy" },
@@ -35,7 +35,7 @@ Example `shell.json` (bar subtree only shown):
       ],
       "center": [
         { "id": "media" },
-        { "id": "daytime", "format": "HH:mm" }
+        { "id": "clock", "format": "HH:mm" }
       ],
       "right": [
         { "id": "audioPanel" },
@@ -58,7 +58,6 @@ Example `shell.json` (bar subtree only shown):
 | `workspaces` | Hyprland workspace switcher | left = focus workspace |
 | `clock` | Date/time label | left = alternate format · right = timezone selector |
 | `media` | MPRIS now-playing — scrolling track + artist, cover-art popup | left = play/pause · middle = next · scroll = prev/next · right = popup |
-| `daytime` | Day/time label with date tooltip | hover = date |
 | `indicators` | Manual state indicators | left = indicator action |
 | `notificationCenter` | Bell with badge + popup with recent notifications, DND toggle | left = popup · right = toggle DND |
 | `systemUpdate` | Available update indicator | left = update |