README: AA 3.5 + 4 screenshots side-by-side with pagination

Replace the single AA 4 + dashboard mix with a paired AA 3.5 / 4 view
of the same Subscriptions index (42 rows paginated to 30, footer shows
totals across all pages). Drop the dashboard/array screenshot and the
styling/footer-values reference tables — too much noise for a README.

Author: Fivell

README.md

@@ -1,11 +1,21 @@
 # activeadmin_table_footer
 
-Adds a `<tfoot>` row to ActiveAdmin index tables with a simple per-column DSL
-and an optional single-query aggregate shared across cells.
+Adds a `<tfoot>` row to ActiveAdmin index tables. Totals are aggregated
+across **all pages** of the filtered scope — not just the visible one — in a
+single SQL query when you use `footer_data:`.
 
 Works with **ActiveAdmin 3.5+ and 4.x**.
 
-![Subscriptions table with footer totals (AA 4)](https://github.com/activeadmin-plugins/activeadmin_table_footer/releases/download/assets-v1/subscriptions_with_footer_4_0.png)
+### ActiveAdmin 4
+
+![Subscriptions index with footer totals on AA 4](https://github.com/activeadmin-plugins/activeadmin_table_footer/releases/download/assets-v1/subscriptions_with_footer_4_0.png)
+
+### ActiveAdmin 3
+
+![Subscriptions index with footer totals on AA 3.5](https://github.com/activeadmin-plugins/activeadmin_table_footer/releases/download/assets-v1/subscriptions_with_footer_3_5.png)
+
+The page shows 30 rows, but the footer row reports the sum across all 42
+subscriptions — that's the point.
 
 ## Install
 
@@ -36,70 +46,14 @@ ActiveAdmin.register Subscription do
 end
 ```
 
-`footer_data:` runs **once** against the filtered scope (without
-`LIMIT/OFFSET/ORDER`), so totals cover every page — not just the visible
-slice. The result is exposed inside each `column :x, footer:` Proc via the
-`footer_data` method.
-
-## `footer:` values
-
-| Value | Behavior |
-|---|---|
-| `String` / Numeric | Rendered as-is |
-| `:sum`, `:count`, `:average`, `:minimum`, `:maximum` | Aggregate over the (unscoped) collection — SQL for AR, Ruby for plain Arrays |
-| `Proc` (arity 0) | Run inside the table — view helpers (`number_to_currency`, `link_to`), Arbre tags (`strong`, `span`), and `footer_data` work |
-| `Proc` (arity 1) | Receives the unscoped collection as argument |
-| `Arbre::Element` | Inserted directly |
-
-Columns without `:footer` render an empty cell so widths align with the
-header. `<tfoot>` itself appears only when at least one column has a footer —
-regular tables are untouched.
-
-## Plain-Array tables
-
-Works the same when `table_for` gets a plain Array (custom panels, dashboards):
-
-![Dashboard with in-memory Array table (AA 3)](https://github.com/activeadmin-plugins/activeadmin_table_footer/releases/download/assets-v1/dashboard_array_table_3_5.png)
-
-```ruby
-table_for items do          # items = [DashboardItem.new(...), ...]
-  column :name, footer: -> { strong { "Totals" } }
-  column :qty,  footer: :sum
-  column :price, footer: ->(arr) { number_to_currency(arr.sum(&:price)) }
-end
-```
-
-Symbol aggregators fall back to `Enumerable` (nil-safe) when the collection
-isn't an AR relation.
-
-## Styling
-
-For AA 4 (Tailwind) sensible defaults are applied. Override globally:
-
-```ruby
-# config/initializers/activeadmin_table_footer.rb
-ActiveadminTableFooter.configure do |c|
-  c.footer_th_class = "px-4 py-3 bg-blue-50 font-bold"
-end
-```
-
-For AA 3 (Sass):
-
-```scss
-.index_table tfoot td {
-  background: #f3f4f6;
-  font-weight: 600;
-  border-top: 1px solid #ddd;
-  padding: 8px 10px;
-}
-```
-
-## Compatibility
+The `footer_data:` Proc runs once over the filtered scope (LIMIT/OFFSET/ORDER
+are stripped automatically). The result is exposed inside each
+`column …, footer: …` Proc via `footer_data`.
 
-| AA | Status |
-|---|---|
-| 4.0.0.beta22 | ✅ |
-| 3.5 | ✅ |
+`footer:` accepts a string, a symbol (`:sum`, `:count`, `:average`,
+`:minimum`, `:maximum`), or a Proc — Procs run inside the table view, so view
+helpers (`number_to_currency`, `link_to`) and Arbre tags (`strong`, `span`)
+work as expected.
 
 ## License