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/app/(dashboard)/[portSlug]/admin/pulse/page.tsx

@@ -24,7 +24,7 @@ export default function PulseAdminPage() {
           <p className="text-muted-foreground">
             Every interest row carries a small coloured chip in the detail header. It scores the
             deal from 0–100 using rule-based signals (no AI). Click the chip on any interest to see
-            the per-signal breakdown — every +N or -N traces back to a dated event on the deal.
+            the per-signal breakdown - every +N or -N traces back to a dated event on the deal.
           </p>
           <p className="text-muted-foreground">
             Positive signals (recent EOI sent, deposit received, contract signed) push the score up.