refactor(ssr): de-fake simple-mode account cursor via explicit render (heuristic 1)

simple-mode-fields* rendered its single account row by rebinding the form cursor to a
synthetic MapCursor rooted at accounts[0] (faking a deep starting position). Replace that
with explicit-data rendering: account-field-name builds the exact field names the cursor
would produce at [:step-params :transaction/accounts 0 field] (via path->name2), and
account-field-errors reads errors from the same path -- no re-rooted cursor.

This is the render-fn rewrite the earlier with-field-default shortcut couldn't be (that
mutated the cursor and broke the simple-mode swap). Scorecard: faked cursor roots 2 -> 0
(both heuristic-1 items now clear for this modal). Parity held: swap spec 6/6 (its vendor
tests run in simple mode), Shared Location save green, full suite 31 pass / no regression.

.claude/skills/ssr-form-migration/reference/scorecard.md

@@ -39,14 +39,15 @@ Each migration appends one row (after-numbers), referencing the before in the di
 | Phase | Modal | LOC | Routes | no-cursor twins | faked roots | snapshot merges | OOB | mixed hx- | cookbook reused / added |
 |-------|-------|-----|--------|-----------------|-------------|-----------------|-----|-----------|-------------------------|
 | 1 (baseline) | Transaction Edit `transaction/edit.clj` | 1608 | ~12 | 1 | 2 | ~75 | 0 | 8 | — / seeded 7 entries |
-| 2 (in progress) | Transaction Edit `transaction/edit.clj` | 1555 | ~12 | **0** | 2 | ~75 | 0 | 8 | — / 0 |
+| 2 (in progress) | Transaction Edit `transaction/edit.clj` | 1570 | ~12 | **0** | **0** | ~75 | 0 | 8 | — / 0 |
 
 > **Phase 2 progress (partial).** Achieved with parity held (swap spec 6/6 + Shared
-> Location green): deleted the dead `*-no-cursor*` twin (no-cursor 1→0, −53 LOC) and fixed
+> Location green, full suite 31 pass / no regression): deleted the dead `*-no-cursor*`
-> a real production bug (`:mode` leaking into the upsert → 500 on every advanced manual
+> twin (no-cursor 1→0), **de-faked the simple-mode cursor** (faked roots 2→0) by rendering
-> save). **Still open** for this modal — and intentionally *not* forced under parity risk:
+> the row from explicit data with explicit field names (`account-field-name`) + explicit
-> faked cursor roots (2 — de-faking needs the render-fn rewrite, see `gotchas.md`), the
+> error lookup — the render-fn rewrite the `with-field-default` shortcut couldn't do — and
-> snapshot round-trip (~75 — removed by the wizard→plain-form reclassification), Selmer
+> fixed a real production bug (`:mode` leaking into the upsert → 500 on every advanced
-> conversion of the render fns, and route collapse (~12 → ~3). These are the bulk of the
+> manual save). **Still open** for this modal: the snapshot round-trip (~75 — removed by
-> modal migration and require restructuring the modal's rendering wholesale rather than
+> the wizard→plain-form reclassification), Selmer conversion of the render fns, and route
-> isolated edits; track as the continuation of Phase 2.
+> collapse (~12 → ~3). These remain the bulk of the migration and need wholesale
+> restructuring of the modal's rendering; track as the continuation of Phase 2.

src/clj/auto_ap/ssr/transaction/edit.clj

@@ -183,10 +183,32 @@
                                  (:account/name (d-accounts/clientize (dc/pull (dc/db conn) d-accounts/default-read value)
                                                                       client-id)))})])
 
+(defn- account-field-name
+  "Explicit form-field name for account row `index`, field `field` -- the same string
+   the form cursor produces at path [:step-params :transaction/accounts index field]
+   (via path->name2), without faking a deep cursor to get there."
+  [index field]
+  (str "step-params[transaction/accounts][" index "]["
+       (if (keyword? field)
+         (str (when (namespace field) (str (namespace field) "/")) (name field))
+         field)
+       "]"))
+
+(defn- account-field-errors
+  "Errors for account row `index`, field `field`, read straight from the form errors
+   at the same path the cursor would walk -- avoids re-rooting a cursor to look them up."
+  [index field]
+  (when (bound? #'fc/*form-errors*)
+    (get-in fc/*form-errors* [:step-params :transaction/accounts index field])))
+
 (defn simple-mode-fields*
   "Renders the simple-mode account + location row and the toggle-to-advanced link.
    Must be called within a fc/start-form + fc/with-field :step-params context.
-   Caller must establish Alpine x-data with simpleAccountId in scope."
+   Caller must establish Alpine x-data with simpleAccountId in scope.
+
+   The single account row is rendered from explicit data with explicit field names
+   (account-field-name 0 ...) rather than faking a synthetic MapCursor rooted at
+   accounts[0] -- the row always lives at index 0 in simple mode."
   [request]
   (let [snapshot (-> request :multi-form-state :snapshot)
         step-params (-> request :multi-form-state :step-params)
@@ -204,34 +226,26 @@
                             (:transaction/amount snapshot)
                             0.0))]
     [:div
-     (fc/with-field :transaction/accounts
-       (fc/with-cursor (let [cur fc/*current*]
-                         (if (sequential? @cur)
-                           (nth cur 0 nil)
-                           (auto_ap.cursor.MapCursor. {} (cursor/state cur) (conj (cursor/path cur) 0))))
      [:span
-          (fc/with-field :db/id
+      (com/hidden {:name (account-field-name 0 :db/id)
-            (com/hidden {:name (fc/field-name)
+                   :value row-id})
-                         :value row-id}))
       [:div.flex.gap-2.mt-2
-           (fc/with-field :transaction-account/account
        (com/validated-field
         {:label "Account"
-               :errors (fc/field-errors)}
+         :errors (account-field-errors 0 :transaction-account/account)}
         [:div.w-72
          (account-typeahead* {:value account-val
                               :client-id client-id
-                                    :name (fc/field-name)
+                              :name (account-field-name 0 :transaction-account/account)
-                                    :x-model "simpleAccountId"})]))
+                              :x-model "simpleAccountId"})])
-           (fc/with-field :transaction-account/location
        ;; Selecting the account only affects the valid Location options, so the
        ;; change swaps just this cell -- nothing else needs to re-render.
        [:div {:id "simple-account-location"}
         (com/validated-field
          {:label "Location"
-                :errors (fc/field-errors)
+          :errors (account-field-errors 0 :transaction-account/location)
           :x-hx-val:account-id "simpleAccountId"
-                :hx-vals (hx/json (cond-> {:name (fc/field-name)}
+          :hx-vals (hx/json (cond-> {:name (account-field-name 0 :transaction-account/location)}
                               client-id (assoc :client-id client-id)))
           :x-dispatch:changed "simpleAccountId"
           :hx-trigger "changed"
@@ -241,13 +255,12 @@
           :hx-swap "outerHTML"
           :hx-include "closest form"}
          (location-select*
-                {:name (fc/field-name)
+          {:name (account-field-name 0 :transaction-account/location)
            :account-location (:account/location account-id)
            :client-locations (pull-attr (dc/db conn) :client/locations client-id)
-                 :value location-val}))])
+           :value location-val}))]
-           (fc/with-field :transaction-account/amount
+       (com/hidden {:name (account-field-name 0 :transaction-account/amount)
-             (com/hidden {:name (fc/field-name)
+                    :value total})]]
-                          :value total}))]]))
      [:div.mt-1
       [:a.text-sm.text-blue-600.hover:underline.cursor-pointer
        {:hx-post (bidi/path-for ssr-routes/only-routes ::route/edit-wizard-toggle-mode)