refactor(ssr): revert hiccup→Selmer migration; render forms in Hiccup again

Abandons the Selmer-templating step of the SSR re-authoring and moves the four
migrated form/wizard modals back to Hiccup (com/* components), keeping the
whole-form HTMX swap doctrine, top-rooted render functions, and the
session-backed wizard engine unchanged.

- transaction/edit, transaction/bulk_code, invoices (bulk-edit group), and
  pos/sales_summaries render via com/* again; every hx-* swap (whole-form +
  targeted location-cell / totals-tbody / inline account-cell swaps) is
  preserved exactly.
- add com/single-modal-card to centralize the md:w-[950px] md:h-[650px] modal
  chrome that previously lived only in the Selmer modal-card templates.
- delete auto-ap.ssr.selmer, auto-ap.ssr.components.selmer, selmer_test, the
  whole resources/templates tree (55 files), the selmer dependency, and the
  tailwind resources/templates content glob.
- strip Selmer guidance from the ssr-form-migration skill + modernization plan.

Verified: all four namespaces compile and render with no stringified-hiccup
leaks; output.css rebuilds byte-identically (no Tailwind class loss); 60 e2e
specs pass — the four reverted modals (incl. whole-form-swap focus/caret tests)
plus the untouched wizard/pay/new/rule modals.

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

project.clj

@@ -96,7 +96,6 @@
                   [org.clojure/core.async]]
 
                  [hiccup "2.0.0-alpha2"]
-                 [selmer "1.12.61"]
 
                  ;; needed for java 11
                  [javax.xml.bind/jaxb-api "2.4.0-b180830.0359"]