feat: add board detail create and filter toolbar UI

AGENTS.md

@@ -97,12 +97,10 @@ Kanbn4Droid is an unofficial app to connect to and manipulate data stored in sel
       - Pressing "Delete" in the modal dialog MUST show a second confirmation modal asking if the user is sure, with buttons for "Cancel" and "I'm sure".
       - Only on pressing "I'm sure" in the second confirmation modal dialog should a board delete request be sent to the API.
     - Long-pressing any of the buttons must show a tooltip with the button name.
-- The view has a floating + button that shows a modal dialog that allows creating a new card using the Kan.bn API.
-  - The new card is added to the top of the currently shown list.
-  - The modal dialog has a field for the card's name. This field is mandatory
-  - Below the card name field there is a markdown-enabled text area for an optional card description.
-  - Below the card description field there is an optional date field to set the card's due date.
-  - Below the card's due date field there is an optional multi-value selector that allows choosing the card's tags from the tags available for the current board.
+- The view has a floating + button that opens a chooser dialog with two options: "Add new list" and "Add new card".
+  - "Add new list" opens a modal dialog with a mandatory list title field and Cancel/Add actions.
+  - "Add new card" opens a modal dialog with mandatory title and optional description fields and Cancel/Add actions.
+  - When the board has no lists, the chooser disables "Add new card" and shows helper text: "Create a list first to add cards."
 - The title bar of the view has two icon-only buttons for "Filter by tag" (icon is three bars of decreasing width, widest on top) and "Search" (icon is a leaning looking glass)
   - The filter by tag button opens a modal dialog that shows a multi-value selector that allows choosing from the tags available on the current board. The modal has a title that says "Filter by tag". The modal has buttons for "Cancel" and "Filter".
   - The search button a modal dialog that shows a text field that has the placeholder value "Search". The modal has a title that seas "Search by title". The modal has buttons for "Cancel" and "Search".
@@ -113,7 +111,7 @@ Kanbn4Droid is an unofficial app to connect to and manipulate data stored in sel
   - Tapping on the filter by tag or search buttonswhen either of them is applied disables the active filter.
 - When a card(s) is selected by a long press, the filter by tag and search buttons get hidden by the select all, move card and delete card buttons until all cards are deselected.
 - When a card(s) is selected by a long press, the back arrow in the title bar and the back system button remove all selections.
-- Current status: implemented in `BoardDetailActivity` with `ViewPager2` (one list per page), inline list-title edit, card rendering (title/tags/due date locale formatting and expiry color), cross-page card selection, page-scoped select-all, move dialog with list selector, two-step delete confirmation, mutation guards while in progress, and API-backed reload/reconciliation behavior through `BoardDetailViewModel` and `BoardDetailRepository`. Card move requests try these variants in order for compatibility across Kan.bn API versions: `PUT /api/v1/cards/{cardPublicId}` with `listPublicId`, then a GET+full-body `PUT /api/v1/cards/{cardPublicId}` payload (`title`, `description`, `index`, `listPublicId`, `dueDate`), then `PUT /api/v1/cards/{cardPublicId}` with `listId`, then `PATCH /api/v1/cards/{cardPublicId}` with `listId`. Board detail parsing now prefers public ids (`publicId`/`public_id`) over internal `id` values so follow-up card/list mutations target the correct API identifiers. Label chip border colors are hydrated from the Kan.bn `Get a label by public ID` endpoint (`colourCode`) and cached in-memory by `BoardDetailRepository` so each label color is fetched only once per app process. Selection action icons use local vector drawables (`ic_select_all_grid_24`, `ic_move_cards_horizontal_24`, `ic_delete_24`) with day/night resource variants so dark mode uses light icon fills automatically. Startup blocking dialogs are shown for missing board id and missing session.
+- Current status: implemented in `BoardDetailActivity` with `ViewPager2` (one list per page), inline list-title edit, card rendering (title/tags/due date locale formatting and expiry color), cross-page card selection, page-scoped select-all, move dialog with list selector, two-step delete confirmation, mutation guards while in progress, create FAB chooser, add-list/add-card dialogs with validation wiring, and toolbar main actions for filter/search that swap with selection actions. Filter/search dialogs are wired and filter/search action icons highlight when active. API-backed reload/reconciliation behavior is handled through `BoardDetailViewModel` and `BoardDetailRepository`. Card move requests try these variants in order for compatibility across Kan.bn API versions: `PUT /api/v1/cards/{cardPublicId}` with `listPublicId`, then a GET+full-body `PUT /api/v1/cards/{cardPublicId}` payload (`title`, `description`, `index`, `listPublicId`, `dueDate`), then `PUT /api/v1/cards/{cardPublicId}` with `listId`, then `PATCH /api/v1/cards/{cardPublicId}` with `listId`. Board detail parsing now prefers public ids (`publicId`/`public_id`) over internal `id` values so follow-up card/list mutations target the correct API identifiers. Label chip border colors are hydrated from the Kan.bn `Get a label by public ID` endpoint (`colourCode`) and cached in-memory by `BoardDetailRepository` so each label color is fetched only once per app process. Selection action icons use local vector drawables (`ic_select_all_grid_24`, `ic_move_cards_horizontal_24`, `ic_delete_24`) with day/night resource variants so dark mode uses light icon fills automatically. Startup blocking dialogs are shown for missing board id and missing session.
 
 **Card detail view**
 - The view shows the card's title in bold letters. Tapping on the card's title allows editing it.