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>

.claude/skills/ssr-form-migration/reference/component-cookbook.md

@@ -1,5 +1,8 @@
 # Component cookbook
 
+> **Note:** Selmer was abandoned — all rendering is Hiccup (`com/*`). Ignore any
+> Selmer/template/`sc/*` references below; use the equivalent `com/*` Hiccup component.
+
 GROWS every migration. Each entry: what it is, the swap rule it uses, and the canonical
 snippet. Reuse these before writing anything new; the success signal is *more reuse each
 migration*.