audit: cycle copy-close tidy — reconcile spec to shipped structure

Cycle-close audit for the case-page copy+close cycle (spec 0002, plan
0003, feat 0308245). Architect drift review + scripts/check.sh.

Regression gate (scripts/check.sh): exit 0 — 0 failures across 19
stages (common/server/clients-desktop/experiments fmt+clippy+build+test,
wearos assembleDebug+lintDebug+testDebugUnitTest), 74s. The single
`wearos :: lintDebug` WARN is pre-existing and untouched by this
frontend-only cycle; not introduced here, carried forward.

Architect findings and resolution:
- [high] template emits two separate close forms, not the spec's single
  #copy-close-form with a has_document label switch. Resolved as a SPEC
  defect, not a code defect: the spec's single-form snippet was
  infeasible — #doc-body exists only in the has-document match arm, so a
  form anchored after it can never serve the documentless case, and it
  must precede the copy <script> to be bound. The shipped two-form split
  is canonical; spec 0002 §Concrete code shapes + §Data flow reconciled
  to it (this commit).
- [high] the spec's `if (!getElementById("doc-body")) return` guard is
  absent from the shipped handler. Not a defect: the no-document form
  carries no id, so the handler (which binds #copy-close-form) never
  attaches to it — the guard is structurally unnecessary. Spec script
  block + prose updated to state this mechanism.
- [medium] the documentless form's distinctness was unpinned. Added an
  assertion to case_page_empty_case_shows_placeholder that the empty
  case renders no #copy-close-form (it is the bare close form).
- [low] plan counter 0003 vs spec counter 0002: not drift — the naming
  policy is per-directory counters (stable_per_directory_4digit over
  [docs/specs, docs/plans]); independent sequences are expected.
- [note] deferred case-list half of #14 leaves a coherent state
  (refs #14, my_cases.html untouched). No drift.

Recommendation: carry-on. No fix iteration needed; the high items were
spec-vs-code reconciliation (docs) and a test guard, both done here.

refs #14

docs/specs/0002-copy-close-on-case-page.md

@@ -41,7 +41,18 @@ server code moves.
 
 What renders directly under the document for an **open** case. For a
 case *with* a document the button copies then closes; for an open case
-*without* a document it is a bare close (nothing to copy):
+*without* a document it is a bare close (nothing to copy).
+
+**Two physically separate forms, not one with a label switch**
+(reconciled to the shipped implementation at audit). `#doc-body` only
+exists in the `{% when Some %}` (has-document) arm of the template's
+`{% match document_html %}`, so a single form anchored after it could
+never serve the documentless case — and it must be emitted *before* the
+copy `<script>` so the submit handler can bind it. The two cases
+therefore live in their two respective match arms:
+
+In the has-document arm, after `#doc-body` — the combined control,
+wired to `copyDocText()`:
 
 ```html
 <div id="doc-body">{{ html|safe }}</div>
@@ -49,11 +60,7 @@ case *with* a document the button copies then closes; for an open case
 <div class="doc-footer-actions">
   <form id="copy-close-form" method="post" action="/cases/{{ case_id }}/close">
     {% call csrf::field(csrf_token) %}
-    {% if has_document %}
     <button type="submit" class="copy-close-btn">Kopieren + Schließen</button>
-    {% else %}
-    <button type="submit" class="copy-close-btn">Schließen</button>
-    {% endif %}
   </form>
   <p id="copy-close-error" class="copy-error" role="alert" hidden>
     Kopieren fehlgeschlagen — Fall nicht geschlossen.
@@ -62,6 +69,21 @@ case *with* a document the button copies then closes; for an open case
 {% endif %}
 ```
 
+In the no-document arm — a bare close form. It carries **no** `id`, so
+the submit handler below (which binds `#copy-close-form`) never attaches
+to it and it submits normally (nothing to copy):
+
+```html
+{% if !is_closed %}
+<div class="doc-footer-actions">
+  <form method="post" action="/cases/{{ case_id }}/close">
+    {% call csrf::field(csrf_token) %}
+    <button type="submit" class="copy-close-btn">Schließen</button>
+  </form>
+</div>
+{% endif %}
+```
+
 The inline script, with the two-path clipboard write extracted into a
 shared function used by both the icon copy button and the close form:
 
@@ -115,11 +137,12 @@ shared function used by both the icon copy button and the close form:
     // the user-gesture context before the form navigates, and a failed
     // copy aborts the close so the user never loses a document they
     // believed was on the clipboard.
+    // Only the has-document form carries id="copy-close-form", so this
+    // handler binds only there; the bare no-document "Schließen" form is
+    // never matched and submits normally (no copy).
     const closeForm = document.getElementById("copy-close-form");
     if (closeForm) {
         closeForm.addEventListener("submit", async (e) => {
-            // Bare "Schließen" (no document) submits normally, no copy.
-            if (!document.getElementById("doc-body")) return;
             e.preventDefault();
             if (await copyDocText()) {
                 closeForm.submit(); // close → 303 → /cases
@@ -184,9 +207,9 @@ No new template variables: `is_closed`, `has_document`, `case_id`, and
 5. On `false`: `#copy-close-error` is unhidden; no submit; case stays
    open.
 
-The bare **Schließen** button (open case, no document) has no
-`#doc-body`, so the handler returns early and the form submits
-normally → same close → `/cases`.
+The bare **Schließen** button (open case, no document) lives in a
+separate form with no `id`, so the submit handler never binds it; it
+submits normally → same close → `/cases`.
 
 ## Error handling