fix(ssr): only require account coding for manual transaction edits

Account coding lived in the always-applied base map of edit-form-schema, so
every action (including the link/apply-rule/unlink actions) required a valid
transaction-account/account. The edit modal always submits the Manual tab's
(usually blank) account row, so link submits failed validation before reaching
their save-handler and silently no-op'd. Move account validation into the
:manual branch of the action :multi so link actions validate without it.

Also surface whole-form validation errors in the wizard footer error bar:
default-step-footer only handled top-level/sequential error shapes, so nested
field-error maps (e.g. a hidden tab's account error) produced an empty bar and
a silent failure. Add flatten-form-errors to flatten the humanized error tree.

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

src/clj/auto_ap/ssr/components/multi_modal.clj

@@ -138,6 +138,33 @@
   [:div.space-y-1 {}
    children])
 
+(defn flatten-form-errors
+  "Walks a malli-humanized error structure and returns a flat sequence of
+   human-readable strings, prefixing each leaf message with the nearest
+   field name for context. Lets the footer's error bar surface every
+   validation error for the whole form, even ones whose field lives on a
+   hidden step/tab and so would otherwise be invisible."
+  ([errors] (flatten-form-errors nil errors))
+  ([field errors]
+   (let [label (cond (keyword? field) (name field)
+                     (string? field) field
+                     :else nil)
+         decorate (fn [msg] (if label (str label ": " msg) msg))]
+     (cond
+       (map? errors)
+       (mapcat (fn [[k v]] (flatten-form-errors k v)) errors)
+
+       (and (sequential? errors) (every? string? errors))
+       (map decorate errors)
+
+       (sequential? errors)
+       (mapcat #(flatten-form-errors field %) errors)
+
+       (string? errors)
+       [(decorate errors)]
+
+       :else nil))))
+
 (defn default-step-footer [linear-wizard step & {:keys [validation-route
                                                         discard-button
                                                         next-button
@@ -146,7 +173,8 @@
    [:div.flex.items-baseline.gap-x-4
     (let [step-errors (:step-params fc/*form-errors*)]
       (com/form-errors {:errors (or (:errors step-errors)
-                                    (when (sequential? step-errors) step-errors))}))
+                                    (when (sequential? step-errors) step-errors)
+                                    (seq (distinct (flatten-form-errors step-errors))))}))
     (when (not= (first (steps linear-wizard))
                 (step-key step))
       (when validation-route