refactor(ssr): collapse 5 manual-coding operation routes into edit-form-changed (heuristic 6)

The 5 manual-coding operations (vendor change, simple/advanced toggle, add row, remove
row, $/% toggle) each had their own route + handler, all doing "mutate form state ->
render-full-form". Fold them into the single edit-form-changed endpoint, which now
dispatches on an `op` form-param to the relevant pure apply-* mutation fn (apply-vendor-
changed / apply-toggle-mode / apply-new-account / apply-remove-account /
apply-toggle-amount-mode) then re-renders. A missing/unknown op (a plain dependent-field
change, e.g. account->location or amount->totals) just re-renders, as before.

- edit.clj: 6 handlers -> 1 dispatcher + 5 pure apply-* fns; markup posts to
  edit-form-changed with :hx-vals {:op "..."}.
- routes/transactions.cljc: remove the 5 now-unused route keys.
- e2e specs: retarget the vendor selector by op (div[hx-vals*="vendor-changed"]) and
  point the toggle-amount-mode / vendor response waits at edit-form-changed, since the
  old per-op route names are gone. (Behavioral assertions unchanged.)

Scorecard: manual-coding routes ~10 -> ~5 (operations now one dispatcher). Parity held:
swap spec 6/6, full suite 32 pass (Shared Location green; no new regression).

e2e/transaction-edit-swap.spec.ts

@@ -48,7 +48,7 @@ async function openManualAdvanced(page: any, transactionIndex = 0) {
 // (Solr is unavailable in tests), click it, and wait for the whole-form swap.
 async function selectVendor(page: any, vendorId: number, label: string) {
   const vendor = page
-    .locator('div[hx-post*="edit-vendor-changed"]')
+    .locator('div[hx-vals*="vendor-changed"]')
     .first()
     .locator('div.relative[x-data]')
     .first();
@@ -62,7 +62,7 @@ async function selectVendor(page: any, vendorId: number, label: string) {
 
   const swap = page.waitForResponse(
     (r: any) =>
-      r.url().includes('edit-vendor-changed') &&
+      r.url().includes('edit-form-changed') &&
       r.request().method() === 'POST' &&
       r.status() === 200
   );
@@ -303,7 +303,7 @@ test.describe('Transaction Edit whole-form swap', () => {
     await page.locator('button[hx-get*="/transaction2/"][hx-get*="/edit"]').nth(0).click();
     await page.waitForSelector('#wizardmodal');
     await page.click('button:has-text("Manual")');
-    await page.waitForSelector('div[hx-post*="edit-vendor-changed"]');
+    await page.waitForSelector('div[hx-vals*="vendor-changed"]');
 
     const testInfo = await (await page.request.get('/test-info')).json();
     const vendorId: number = testInfo.accounts.vendor;
@@ -311,7 +311,7 @@ test.describe('Transaction Edit whole-form swap', () => {
 
     // Drive the vendor typeahead like a user: open dropdown, inject a result
     // (Solr is unavailable in tests), click it.
-    const vendor = page.locator('div[hx-post*="edit-vendor-changed"]').first().locator('div.relative[x-data]').first();
+    const vendor = page.locator('div[hx-vals*="vendor-changed"]').first().locator('div.relative[x-data]').first();
     await vendor.locator('a[x-ref="input"]').click();
     const search = page.locator('[data-tippy-root] input[x-model="search"]').first();
     await search.waitFor({ state: 'visible' });
@@ -322,7 +322,7 @@ test.describe('Transaction Edit whole-form swap', () => {
 
     const swap = page.waitForResponse(
       (r: any) =>
-        r.url().includes('edit-vendor-changed') &&
+        r.url().includes('edit-form-changed') &&
         r.request().method() === 'POST' &&
         r.status() === 200
     );
@@ -352,7 +352,7 @@ test.describe('Transaction Edit whole-form swap', () => {
     await page.locator('button[hx-get*="/transaction2/"][hx-get*="/edit"]').nth(0).click();
     await page.waitForSelector('#wizardmodal');
     await page.click('button:has-text("Manual")');
-    await page.waitForSelector('div[hx-post*="edit-vendor-changed"]');
+    await page.waitForSelector('div[hx-vals*="vendor-changed"]');
 
     const testInfo = await (await page.request.get('/test-info')).json();
     const vendor1: number = testInfo.accounts.vendor;
@@ -361,7 +361,7 @@ test.describe('Transaction Edit whole-form swap', () => {
     const account2: number = testInfo.accounts['second-account'];
 
     const vendorLabel = page
-      .locator('div[hx-post*="edit-vendor-changed"] span[x-text="value.label"]')
+      .locator('div[hx-vals*="vendor-changed"] span[x-text="value.label"]')
       .first();
     const accountHidden = page
       .locator('input[type="hidden"][name*="transaction-account/account"]')