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/api/v1/expenses/[id]/merge/route.ts

@@ -7,7 +7,7 @@ import { errorResponse } from '@/lib/errors';
 import { mergeDuplicate } from '@/lib/services/expense-dedup.service';
 
 const mergeSchema = z.object({
-  /** Surviving expense id — typically the row's existing `duplicateOf` pointer. */
+  /** Surviving expense id - typically the row's existing `duplicateOf` pointer. */
   targetId: z.string().min(1),
 });
 

src/app/api/v1/expenses/scan-receipt/route.ts

@@ -51,7 +51,7 @@ export const POST = withAuth(
           });
         }
 
-        // Per-port budget gate — refuse the call before we spend tokens
+        // Per-port budget gate - refuse the call before we spend tokens
         // when the port has already hit its hard cap, or when the request
         // would push it past the cap. Soft-cap warnings ride along on the
         // success response so the UI can show a banner without blocking.
@@ -99,7 +99,7 @@ export const POST = withAuth(
           });
         } catch (err) {
           logger.error({ err, provider: config.provider }, 'OCR provider call failed');
-          // Provider hiccup — degrade to manual entry rather than 500-ing.
+          // Provider hiccup - degrade to manual entry rather than 500-ing.
           return NextResponse.json({
             data: {
               parsed: EMPTY,