polish(dashboard): downgrade the build-assistant hero to the quiet-sentence promo (#1731)

Replace the boxed Card hero on Hem with AgentPromo, a clone of the
SkatteverketPromoCard pattern: one 12.5px muted sentence with the action
link at the end, '(beta)' as a word in the sentence, and a per-company
'Dölj förslaget' dismiss persisted in localStorage
(erp_agent_promo_dismissed:<companyId>) via useSyncExternalStore.

Removes the hover:border-primary/50 opacity border and the arrow
translate (both against design.md). Gate (!agentBuilt and checklist
dismissed/completed) and hasAi ? /onboarding/agent : /settings/billing
routing unchanged; SkatteverketPromoCard mutual exclusion on agentBuilt
unchanged. Copy moved to dashboard.agent_promo_* in sv+en.

Co-authored-by: Jakob Wennberg <311770904+jakobwennberg-oss@users.noreply.github.com>
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

messages/en.json

@@ -6395,6 +6395,11 @@
     "skv_promo_description": "See your tax account and file VAT and employer declarations directly from here. Connect with BankID in a couple of minutes.",
     "skv_promo_cta": "Connect",
     "skv_promo_dismiss": "Dismiss suggestion",
+    "agent_promo_description": "Build your bookkeeping assistant (beta): a few questions about your business calibrate an assistant that suggests bookkeeping for you.",
+    "agent_promo_description_upgrade": "The bookkeeping assistant (beta) is included in the subscription: an assistant that suggests bookkeeping for you.",
+    "agent_promo_cta": "Get started",
+    "agent_promo_cta_upgrade": "Upgrade",
+    "agent_promo_dismiss": "Dismiss suggestion",
     "result": "Net result",
     "this_year_short": "this year",
     "this_month": "this month",

messages/sv.json

@@ -6395,6 +6395,11 @@
     "skv_promo_description": "Se skattekontot och lämna moms- och arbetsgivardeklarationer direkt härifrån. Anslut med BankID på ett par minuter.",
     "skv_promo_cta": "Anslut",
     "skv_promo_dismiss": "Dölj förslaget",
+    "agent_promo_description": "Bygg din bokföringsassistent (beta): några frågor om din verksamhet kalibrerar en assistent som föreslår bokföring åt dig.",
+    "agent_promo_description_upgrade": "Bokföringsassistenten (beta) ingår i abonnemanget: en assistent som föreslår bokföring åt dig.",
+    "agent_promo_cta": "Kom igång",
+    "agent_promo_cta_upgrade": "Uppgradera",
+    "agent_promo_dismiss": "Dölj förslaget",
     "result": "Resultat",
     "this_year_short": "i år",
     "this_month": "denna månad",