docs(skill): distil ssr-form-migration skill from transaction-edit reference (Phase 1)

Capture the proven whole-form hx-select swap method as a reusable skill so every
later modal migration is cheaper and consistent. No app code changes.

- SKILL.md: the per-migration playbook (classify → baseline → characterize →
  consolidate render fns → templatize → wire HTMX → collapse routes → verify →
  commit → feed skill) + Growth contract + non-negotiables.
- reference/swap-doctrine.md: the four swap rules, focus invariant, Alpine-survives-
  swap hardening, target-selector strategy — worked from the real edit.clj swaps
  (memo no-request, account→location targeted cell, amount→totals sibling-tbody,
  vendor/mode/row whole-form). 0 OOB.
- reference/render-functions.md: explicit-data or top-rooted cursor; the MapCursor
  fake + transaction-account-row-no-cursor* twin as the smell to remove.
- reference/form-vs-wizard.md: classification + the data-driven session-backed
  (formtools SessionStorage) engine that replaces the snapshot round-trip + protocol.
- reference/selmer-conventions.md: STUB, validated in Phase 2.
- component-cookbook.md / gotchas.md / test-recipes.md / scorecard.md: seeded from
  what transaction-edit proves (7 cookbook entries, caret-survival + typeahead test
  recipes, scorecard baseline LOC 1608 / ~12 routes / 1 no-cursor twin / 2 faked
  roots / 0 OOB).

Scorecard (Transaction Edit baseline, before Phase 2): LOC 1608, routes ~12,
no-cursor twins 1, faked-cursor roots 2, snapshot merges ~75, OOB 0, mixed hx- 8.

.claude/skills/ssr-form-migration/reference/test-recipes.md

@@ -0,0 +1,89 @@
+# Test recipes
+
+GROWS every migration. How to characterize and verify a modal. Consistent with the
+project `testing-conventions` skill: test user-observable behavior, assert DB state
+directly, don't test the means.
+
+## The three test layers
+
+1. **Characterization e2e first (Playwright).** Before changing a modal, write/confirm a
+   spec capturing *current* behavior — focus/caret survival across swaps, each field
+   round-trip, validation errors, the real save. This is the parity contract; keep it
+   green through every commit.
+2. **Pure-function checks via REPL.** Once render/data-prep fns are pure, exercise them
+   with `clojure-eval` / `clj-nrepl-eval -p <port>`. Assert on returned data; for markup
+   use string matches (`(re-find #"accounts\[0\]\[account\]" (str html))`) — this style
+   survives the Selmer switch. Avoid brittle structural assertions.
+3. **DB-state assertions for mutations.** If a submit writes Datomic, verify by querying
+   the DB, not by asserting on markup.
+
+## Running e2e
+
+```bash
+npx playwright test                              # full suite
+npx playwright test e2e/transaction-edit-swap.spec.ts   # one spec
+```
+- Config: `playwright.config.ts`, `baseURL http://localhost:3333`, `webServer:
+  lein run -m auto-ap.test-server`, `reuseExistingServer: !CI`.
+- **The server must be from the worktree you're testing.** `reuseExistingServer` will
+  silently reuse *any* server on `:3333` — including another worktree's. Confirm with
+  `ls -la /proc/$(lsof -ti :3333)/cwd` (or restart on a clean port) before trusting a run.
+- The test-server port is hardcoded (`test_server.clj` `run-jetty {:port 3333}`); to run a
+  second server from another worktree, change that or parameterise it.
+
+## Driving a typeahead in e2e (Solr unavailable in tests)
+
+```js
+await typeahead.locator('a[x-ref="input"]').click();      // open tippy dropdown
+const search = page.locator('[data-tippy-root] input[x-model="search"]').first();
+await search.fill('te');                                  // under 3-char Solr threshold
+await typeahead.evaluate((el, id) => {                     // inject a clickable result
+  window.Alpine.$data(el).elements = [{ value: id, label: 'Test Account' }];
+}, accountId);
+await page.locator('[data-tippy-root] a', { hasText: 'Test Account' }).first().click();
+```
+Entity ids come from `GET /test-info` (`{accounts:{test-account, vendor, vendor2, ...}}`).
+
+## Proving the focus invariant (caret survival) — the key swap test
+
+```js
+// before the debounced swap lands, capture the live focused node...
+await page.evaluate(() => { window.__focused = document.activeElement; });
+await swap;                                       // waitForResponse on the *-form-changed POST
+const ok = await page.evaluate(() => {
+  const a = document.activeElement;
+  return { sameNode: a === window.__focused, value: a?.value, caret: a?.selectionStart };
+});
+// ...assert the SAME node survived with value + caret intact.
+```
+`trackErrors(page)` (collect `pageerror` + `console.error`, assert `[]`) catches a swap
+that throws on a stale `$refs`/`tippy` — pair it with every swap test.
+
+## Asserting "no request" (Rule 1 fields)
+
+```js
+let posts = 0;
+page.on('request', r => { if (r.url().includes('edit-form-changed') && r.method()==='POST') posts++; });
+// ...type in the memo...
+expect(posts).toBe(0);   // memo affects nothing → issues no request
+```
+
+---
+
+## E2E baseline (the regression gate — never drop below this)
+
+The full suite must stay green after every migration. Specs touching the migrated modals:
+
+| Spec | Tests | Role |
+|------|-------|------|
+| `e2e/transaction-edit-swap.spec.ts` | 8 | **Phase 2 parity contract** — whole-form `hx-select` swaps, caret survival, no-request memo, vendor re-select |
+| `e2e/transaction-edit.spec.ts` | 15 | transaction edit behavior |
+| `e2e/bulk-code-transactions.spec.ts` | 18 | Phase 3 (bulk code) |
+| `e2e/transaction-import.spec.ts` | 4 | import |
+| `e2e/transaction-navigation.spec.ts` | 13 | navigation |
+
+**Pass/fail baseline: TO BE CAPTURED at the first Phase 2 e2e run** against a test server
+booted from *this* worktree (`integreat-execute-refactor`). At distillation time `:3333`
+was occupied by the `integreat-render-whole-form` worktree (morph version), so a run then
+would not reflect the merged hx-select reference. Record the green count here once
+captured, and never drop below it.