refactor(ssr): compose the bulk-code form entirely in Selmer

Each bulk-code route now ends in a single sel/render call; all composition
(modal chrome, body, account grid, rows, footer, errors) happens in the
templates via {% extends %}/{% block %}/{% include %}/{% with %}, reading one
nested view-model (form-ctx). No HTML is stitched together in Clojure.

- Add components/modal-card.html: a base chrome with head/body/footer blocks;
  bulk-code/card.html extends it. (Transaction Edit keeps its string-slot
  edit-modal.html for now.)
- New top-level templates: open.html, form.html, card.html, body.html; rework
  account-grid/account-row/footer/head to pull the shared component partials in
  via {% include %}+{% with %} instead of hardcoding class strings or receiving
  pre-rendered HTML strings.
- render-form / open-handler collapse to one sel/render of form.html / open.html.
  bulk-code-body*, footer*, form-errors-html, account-grid*, the *errors* dynamic
  var and ferr are gone; field errors are read straight from :form-errors.
- Extract sc/{select,button,a-button,a-icon-button}-ctx so templates can include
  those partials with computed context (the render wrappers now call the -ctx fns).

Verified: rendered output is DOM-identical to the prior version across empty /
populated / error scenarios (whitespace-normalized token compare), plus browser
QA (open, vendor auto-populate, add/remove row, typeahead, per-row location swap,
percentage validation, submit); no JS errors.

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

resources/templates/transaction-bulk-code/head.html

@@ -1,2 +1,2 @@
 {# Modal header label: how many transactions this bulk-code operation will touch. #}
-<div class="p-2">Bulk editing {{ count }} transactions</div>
+<div class="p-2">Bulk editing {{ head_count }} transactions</div>