chore(copy): em-dash sweep across user-facing JSX text + bump lint to error

Replaced 174 em-dashes (—) with " - " (space-hyphen-space) across 49
files in src/components + src/app. The em-dash reads as a tell-tale
"AI-generated" marker per the user's design feedback; hyphens with
spaces preserve the connector semantics without the AI tint.

Touched only lines outside pure-comment context (// /* * */). Code
comments, JSDoc, audit-log strings, structured logging strings, and
templates outside the lint scope retain their em-dashes for now —
they're not user-visible.

Also captured two remaining cases that used the `—` HTML entity
instead of the literal character (system-monitoring-dashboard,
interest-stage-picker) — replaced with a plain hyphen.

Bumped the existing `no-restricted-syntax` rule from `warn` → `error`
in eslint.config.mjs scoped to src/components/**/*.tsx +
src/app/**/*.tsx. New code reintroducing em-dashes in JSX text now
fails the lint gate.

Verified: tsc clean, vitest 1448/1448, eslint 0 em-dash warnings.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/components/admin/documenso/embedded-signing-card.tsx

@@ -72,7 +72,7 @@ export function EmbeddedSigningCard() {
       };
       setResult({ ...res.data, at: new Date() });
       if (res.data.ok) toast.success('Embedded signing host reachable.');
-      else toast.error('Embedded signing host probe failed — see card.');
+      else toast.error('Embedded signing host probe failed  -  see card.');
     } catch (err) {
       toastError(err);
       setResult({
@@ -200,7 +200,7 @@ export function EmbeddedSigningCard() {
               <p className="text-muted-foreground">
                 The marketing site needs to handle <code>/sign/[role]/[token]</code> by forwarding
                 to the underlying Documenso signing URL (or embedding it in an iframe). Role is one
-                of <code>client</code> / <code>developer</code> / <code>approver</code> — useful for
+                of <code>client</code> / <code>developer</code> / <code>approver</code> - useful for
                 tracking which slot the signer is in.
               </p>
               <p className="mt-1 text-muted-foreground">Minimum Next.js example:</p>
@@ -228,7 +228,7 @@ export default function SignPage({ params }) {
               <p className="text-muted-foreground">
                 Use the Test connection button to verify <code>/</code> and{' '}
                 <code>/sign/success</code> return 2xx. If either fails, the marketing site
-                isn&apos;t ready — fix the route before flipping live or signers will land on a 404
+                isn&apos;t ready - fix the route before flipping live or signers will land on a 404
                 page from outbound emails.
               </p>
             </section>