refactor(ssr): Phase 3 — full Selmer migration of Transaction Bulk Code; remove the wizard

Migrates the Transaction Bulk Code modal (a single-step form wearing a full
wizard costume) to a plain Selmer form, cold-applying the ssr-form-migration
skill. Almost entirely reuse of the Phase-2 work: the whole `sc/*` Selmer
component library, `account-typeahead*` / `location-select*`, and the
`edit-modal` / `transitioner` chrome are imported wholesale.

What changed
- Wizard removed: deleted `BulkCodeWizard` / `AccountsStep` records,
  `MultiStepFormState`, the `step-params[...]` prefix, and all `mm/*`
  middleware. Replaced with a plain handler + flat `wrap-bulk-state` (decode
  straight into `bulk-code-schema`, no snapshot round-trip).
- Selection round-trip: the non-editable transaction selection is resolved to
  a concrete not-locked id vector at open and ridden back in hidden `ids[]`
  fields (the bulk analog of edit's single `db/id`) — no EDN snapshot, no
  filter re-query, and more correct (codes exactly the rows the user saw).
- 100% Selmer render path (only the shared terminal `com/success-modal` keeps
  Hiccup — heuristic-9 exception). New shared component `sc/select`
  (`location-select.html` generalized) for the status dropdown.
- Routes 4 -> 3: GET `bulk-code` (open), POST `bulk-code-submit`, POST
  `bulk-code-form-changed` (one whole-form op dispatcher folding the old
  `new-account` + `vendor-changed` routes). Location swap moved off `find *`
  onto explicit `#account-location-<index>` + `hx-select`.
- Fixed a latent correctness bug surfaced by the migration: the vendor
  typeahead needs `:id` (value-keyed `:key`) or its value-bound hidden goes
  stale across a whole-form swap and posts blank.

Scorecard delta (transaction/bulk_code.clj): mm coupling 19->0, snapshot
merges 4->0, wizard records 3->0, step-params 10->0, routes 4->3, OOB 0,
Hiccup-in-render ->0 (bar success-modal). LOC 420->506 (documented exception:
the wizard was a thin shell over mm/* defaults, so explicitness moves shared
plumbing into the file). Cookbook: reused the entire Phase-2 sc/* lib + chrome,
added sc/select.

Verification: bulk-code-transactions.spec.ts 13/13; full Playwright suite
39/39; cljfmt clean.

Skill fed: scorecard row + narrative + LOC exception; gotchas (value-bound
typeahead keying, selection-as-ids round-trip); cookbook (sc/select).

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

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

@@ -164,6 +164,7 @@ the interop bridge; dynamic HTMX/Alpine attrs go through `sc/attrs->str` →
 | Wrapper | Partial | Notes |
 |---------|---------|-------|
 | `sc/hidden` / `sc/text-input` / `sc/money-input` | `hidden`/`text-input`/`money-input`.html | leaf inputs; class via `inputs/default-input-classes` + `use-size` |
+| `sc/select` (Phase 3) | `select.html` | generic `<select>`; `options [[value label] …]`, `:value` (string/keyword) marks selected, extra hx-/x- attrs ride through. `location-select.html` generalized — reach for this before `com/select`. Added for the bulk-code status field. |
 | `sc/validated-field` | `validated-field.html` | label + body + always-present error `<p>`; pass-through attrs land on the wrapping div (the per-row location cell hangs its swap wiring here) |
 | `sc/button` / `sc/a-button` / `sc/a-icon-button` | `button`/`a-button`/`a-icon-button`.html | spinner via `{% include "spinner.html" %}`; class via `btn/bg-colors` |
 | `sc/badge` / `sc/link` | `badge`/`link`.html | |

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

@@ -198,8 +198,45 @@ Post-adoption baseline is **39 pass / 0 fail** — the previously-flaky
 `transaction-navigation.spec.ts` date-range test is now green, because `/test-reset` removes
 the residual mutation it was tripping over.
 
+## A value-bound typeahead hidden goes stale across a whole-form swap unless keyed
+
+A typeahead (`sc/typeahead`) posts its value through a hidden `<input :value="value.value">`
+whose DOM `.value` is set by Alpine, not by the server-rendered static `value` attr. After a
+**whole-form `outerHTML` swap** that re-renders the typeahead, Alpine may preserve the *previous*
+component's empty `.value` instead of binding the new server value — so the field posts blank
+on the next submit. Fix: pass **`:id`** to `sc/typeahead` (the account typeahead already does).
+`:id` makes the wrapper emit `:key (str id "--" value)`, and the value-keyed `:key` forces a
+clean Alpine re-init that lands the server value. The bulk-code *vendor* typeahead hit this
+(account rows didn't, because they pass `:id`) — symptom: "vendor not preserved on a validation
+re-render." Note the testing trap: reading the hidden's `.value` in isolation
+(`inputValue()` / `toHaveValue`) is an unreliable probe — it lags Alpine. Assert what the form
+**actually posts** instead: `new FormData(form).get('vendor')` (wrap in `expect.poll`).
+
+## Round-trip a multi-row selection as `ids[]`, not as an EDN/filter snapshot
+
+A bulk modal acts on a *selection* of N entities (bulk-code: the checked transactions), the
+analog of a single modal's one `db/id`. The wizard stashed the whole search-params blob (filters
++ `selected` + `all-selected`) in the EDN snapshot and re-ran the filter query on every post.
+Don't carry that forward. Instead **resolve the selection to a concrete id vector once at open**
+(`selected->ids` → the not-locked set) and ride it back in hidden `ids[0..n]` fields; re-read it
+on each post (`[:vector {:coerce? true} entity-id]` + the `coerce-vector` transformer turns the
+`{"0" "123"}` index-map into `[123]`). No snapshot, no filter round-trip, and it's *more* correct
+— you code exactly the rows the user saw, immune to data changing between open and submit. This
+is heuristic 2 → 0 for a multi-select modal.
+
 ## Scorecard exceptions (ratchet violations with a reason)
 
+**Heuristic 4 (LOC net ↓) — exception (Phase 3, Transaction Bulk Code: 420→506).** When the
+modal's wizard was a *thin* shell that delegated almost everything to `mm/*` defaults
+(`default-render-step`, `default-render-wizard`, `submit-handler`, `open-wizard-handler`),
+ripping the wizard out moves that previously-shared plumbing **into the file** as explicit
+render/decode/submit/handler code, so the single-file LOC rises even though total system
+complexity drops. This is the opposite of a fat wizard (edit went 1608→1548). The trade is
+intended and every other heuristic improved sharply (mm coupling 19→0, snapshot merges 4→0,
+wizard records 3→0, routes 4→3, `find *`→explicit-id swap). Watch for it on the small
+"single-step wearing a wizard costume" modals — LOC is the wrong headline metric there;
+the mm-coupling / snapshot / route counts are.
+
 **Heuristic 9 (Hiccup in render path) — partial exception (Phase 2-final).** The post-save
 `com/success-modal` confirmation dialogs in `save-handler` keep ~6 `[:p …]` Hiccup lines.
 They are terminal responses (shown after the form closes), reuse a shared dialog component,

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

@@ -41,6 +41,9 @@ Each migration appends one row (after-numbers), referencing the before in the di
 | 1 (baseline) | Transaction Edit `transaction/edit.clj` | 1608 | ~12 | 1 | 2 | ~75 | 0 | 8 | — / seeded 7 entries |
 | 2 | Transaction Edit `transaction/edit.clj` | 1593 | **~5** | **0** | **0** | **0 round-trip** | 0 | 8 (shared) | location-select / **1 Selmer** |
 | 2-final | Transaction Edit (full Selmer + wizard removed) | 1548 | **5** | 0 | 0 | 0 | 0 | **0** | full `sc/*` lib / **~30 partials** |
+| 3 | Transaction Bulk Code `transaction/bulk_code.clj` | 506 (was 420 — see exception) | **3** | 0 | 0 | **0** | 0 | 0† | reused **all** of Phase-2's `sc/*` lib + `account-typeahead*`/`location-select*` + `edit-modal`/`transitioner` chrome / added **`sc/select`** |
+
+† The one `"hx-..."` string hit is a response-header map (`{"hx-trigger" "refreshTable, reset-selection"}`), not a mixed attribute encoding. mm coupling 19→**0**, wizard records 3→**0**, step-params 10→**0** (the 2 hits are comments), Hiccup-in-render → **0** except the shared `com/success-modal` (heuristic-9 exception, as in Phase 2).
 
 ### New heuristics introduced at 2-final (full Selmer)
 
@@ -82,3 +85,26 @@ Each migration appends one row (after-numbers), referencing the before in the di
 > shared component — out of the form's render path). See `form-vs-wizard.md` (drop-the-
 > wizard test), `selmer-conventions.md` (composition mechanics), and `gotchas.md`
 > (stray-field decode leak; jetty reload staleness).
+
+> **Phase 3 — Transaction Bulk Code (first cold apply of the mature skill).** Single-step
+> form wearing a full wizard costume (`BulkCodeWizard`/`AccountsStep`, `MultiStepFormState`,
+> the `step-params[...]` prefix, the old `find *` location swap). Migrated to a plain form by
+> mirroring Phase 2 — and it was mostly **reuse**: the entire `sc/*` Selmer component library,
+> `account-typeahead*`/`location-select*`, and the `edit-modal`/`transitioner` chrome were
+> imported wholesale; the only new shared component was **`sc/select`** (the status dropdown —
+> `location-select.html` generalized). Parity held: bulk-code spec **13/13**, full suite
+> **39/39** (up from the Phase-2 baseline of 38–39). mm coupling 19→0, snapshot merges 4→0,
+> wizard records 3→0, routes 4→3 (open / submit / `form-changed` — the per-op `new-account` +
+> `vendor-changed` routes folded into one `form-changed` op dispatcher), the location swap moved
+> off `find *` onto explicit `#account-location-<index>` + `hx-select`.
+>
+> **The one regression — LOC 420→506 (documented exception, see `gotchas.md`).** Unlike edit
+> (whose wizard held real custom code), bulk-code's wizard was a *thin* shell that delegated
+> almost everything to `mm/*` defaults (`default-render-step`, `default-render-wizard`,
+> `submit-handler`, `open-wizard-handler`). Ripping the wizard out moves that
+> previously-shared plumbing **into the file** as explicit render/decode/submit/handler code.
+> The trade is intended: every other heuristic improved and the modal is now self-contained
+> and wizard-free. New patterns added to the cookbook: the **selection-as-`ids[]` round-trip**
+> (resolve the non-editable selection to a concrete id vector at open, ride it in hidden
+> fields — the bulk analog of edit's single `db/id`), and the **`:id`-keyed vendor typeahead**
+> (a value-bound hidden must be keyed or its posted value goes stale across a whole-form swap).