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/shared/registry-driven-form.tsx

@@ -616,7 +616,7 @@ function UserSelectInput({
         <SelectValue placeholder={isLoading ? 'Loading users…' : placeholder} />
       </SelectTrigger>
       <SelectContent>
-        <SelectItem value={NONE}>— No CRM user linked —</SelectItem>
+        <SelectItem value={NONE}> - No CRM user linked - </SelectItem>
         {(data?.data ?? []).map((u) => (
           <SelectItem key={u.id} value={u.id}>
             {u.name || u.email} {u.name ? `· ${u.email}` : ''}