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/interests/deal-pulse-chip.tsx

@@ -57,7 +57,7 @@ export function DealPulseChip({ interest }: { interest: DealHealthInput }) {
       <PopoverContent side="bottom" align="start" className="w-80 p-4 space-y-3">
         <div>
           <p className="text-sm font-semibold">
-            Deal pulse — {label} ({health.score} / 100)
+            Deal pulse - {label} ({health.score} / 100)
           </p>
           <p className="mt-0.5 text-xs text-muted-foreground">
             How likely this deal is to keep moving forward, scored from 0 to 100.
@@ -70,7 +70,7 @@ export function DealPulseChip({ interest }: { interest: DealHealthInput }) {
           </p>
           {health.signals.length === 0 ? (
             <p className="mt-1 text-xs text-muted-foreground">
-              Nothing notable yet — the score is sitting at the baseline (50). Log a contact,
+              Nothing notable yet - the score is sitting at the baseline (50). Log a contact,
               progress the stage, or send a signing request and you&apos;ll see the dial move.
             </p>
           ) : (