🌐 Keep unused placeholders out of the gate

Reverts the %s-stripping on unused auth.terms-privacy-agreement:
the links mirror its markdown sibling and a reactivation may
need them. Placeholder mismatches on #, unused keys now warn
instead of failing, and the rule is recorded in
mem:frontend/translations.

AI-assisted-by: muse-spark-1.3-contributor

.serena/memories/frontend/translations.md

@@ -69,7 +69,9 @@ high-coverage support reference, never the base.
 - Placeholder parity per entry (singular AND each plural form,
   also enforced by the script); verify `%s` against the `tr` call
   site when `en`/`es`/code disagree (a `%s` the code never passes
-  renders literally; a dropped one swallows the argument).
+  renders literally; a dropped one swallows the argument). On
+  `#, unused` keys the script only warns: never "fix" them by
+  deleting placeholders or links, a reactivation may need them.
 - Glued words (AI batches drop spaces at wrap boundaries): the
   script flags function-word splits (`del'equip`, `lapolítica`,
   `sinecessiteu`), `,/.`/`:` without following space,

frontend/scripts/translations.js

@@ -604,11 +604,17 @@ async function check(locale, words) {
       const textEs = textsEs[i] ?? "";
       const refs = refToks(textEn, textEs);
       if (textEn) {
+        const unused = (e.comments?.flag ?? "")
+          .split(/,\s*/)
+          .includes("unused");
         for (const re of PLACEHOLDER_RES) {
           const nEn = countIn(textEn, re);
           const nLoc = countIn(text, re);
           if (nEn !== nLoc) {
-            errors.push(
+            // Unused keys are never rendered: report, don't fail.
+            // "Fixing" them by deleting placeholders can destroy
+            // content that a reactivation may need.
+            (unused ? warnings : errors).push(
               `${msgid}[${i}]: placeholder mismatch ${re.source}: en=${nEn} ${locale}=${nLoc}`,
             );
           }

frontend/translations/es.po

@@ -196,8 +196,8 @@ msgstr "Términos de servicio"
 #, unused
 msgid "auth.terms-privacy-agreement"
 msgstr ""
-"Al crear una nueva cuenta, aceptas nuestros términos de servicio y política "
-"de privacidad."
+"Al crear una nueva cuenta, aceptas nuestros [términos de servicio](%s) y "
+"[política de privacidad](%s)."
 
 #: src/app/main/ui/auth/register.cljs:238
 #, unused