chore(style): codebase em-dash sweep + minor layout polish

Replaces every em-dash and en-dash with regular ASCII hyphens
across comments, JSX strings, and dev-facing logs. Mostly cosmetic
but stops the inconsistent mix that crept in over the last few
months (some files used em-dashes in comments, others didn't,
some used both).

Bundles two small dashboard-layout tweaks that touch a couple of
already-modified files:
- (dashboard)/layout.tsx main padding goes from p-6 to pt-3 px-6
  pb-6 so page content sits closer to the topbar.
- Sidebar now receives the ports list it needs for the footer
  port switcher.

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

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

@@ -34,7 +34,7 @@ const FIELDS: SettingFieldDef[] = [
     label: 'Default signature (HTML)',
     description: 'Appended to the bottom of system-generated emails.',
     type: 'html',
-    placeholder: '<p>—<br>The Port Nimara team</p>',
+    placeholder: '<p>-<br>The Port Nimara team</p>',
     defaultValue: '',
   },
   {
@@ -71,7 +71,7 @@ const FIELDS: SettingFieldDef[] = [
   {
     key: 'smtp_pass_override',
     label: 'SMTP password override',
-    description: 'Optional. Stored in plain text — only set when overriding env credentials.',
+    description: 'Optional. Stored in plain text - only set when overriding env credentials.',
     type: 'password',
     defaultValue: '',
   },