feat(agent): move 'Vad din agent vet' into settings (Assistenten -> Kunskap) (#1008)

Relocates the ledger-knowledge surface off the top nav and into the
assistant settings hub as a third tab (Minne / Kompetens / Kunskap), per
the code's own "minne + kunskap under Assistenten" intent and the #935
flag that this was an easy call to change.

Because both settings surfaces (the full-page rail and the intercepting
settings modal) mount each section as a propless component via
SETTINGS_SECTIONS, the knowledge data must be fetched client-side rather
than passed as a server prop:

- New GET /api/agent/knowledge aggregates buildLedgerContext +
  buildDeepEntities + buildAgentCompetence + company name (read-only,
  company-scoped via withRouteContext).
- AgentKnowledgeView + AgentCompetenceSections converted from async
  server components to client components (getTranslations ->
  useTranslations; no other server-only usage).
- New AgentKnowledgePanel client wrapper lazy-fetches the payload when
  the Kunskap tab opens (Radix unmounts inactive tabs), with Skeleton and
  error states matching the memory/skills panels.
- Removed the Brain/agent-knowledge entry (and its now-unused import)
  from the Analys nav group.
- /agent-knowledge kept as a redirect to /settings/assistant?view=knowledge
  so old links/bookmarks resolve.

Tests: new route test (auth 401, no-company 400, happy-path aggregation).
i18n: load_error_* keys added to both locales (parity kept).

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

components/agent-knowledge/AgentCompetenceSections.tsx

@@ -1,4 +1,6 @@
-import { getTranslations } from 'next-intl/server'
+'use client'
+
+import { useTranslations } from 'next-intl'
 import Link from 'next/link'
 import { Pin, ArrowUpRight } from 'lucide-react'
 import { Card, CardHeader, CardTitle, CardDescription, CardContent } from '@/components/ui/card'
@@ -14,8 +16,8 @@ import type { AgentCompetence, AtomTier, FactKind, FactSource } from '@/lib/agen
 
 const TIER_ORDER: AtomTier[] = ['horizontal', 'vertical', 'modifier']
 
-export async function CompetenceCard({ competence }: { competence: AgentCompetence }) {
-  const t = await getTranslations('agentKnowledge')
+export function CompetenceCard({ competence }: { competence: AgentCompetence }) {
+  const t = useTranslations('agentKnowledge')
   const { atoms } = competence
   const activeAtoms = atoms.filter((a) => a.active).length
   const tierLabel = (tier: AtomTier) =>
@@ -69,8 +71,8 @@ export async function CompetenceCard({ competence }: { competence: AgentCompeten
   )
 }
 
-export async function FactsCard({ competence }: { competence: AgentCompetence }) {
-  const t = await getTranslations('agentKnowledge')
+export function FactsCard({ competence }: { competence: AgentCompetence }) {
+  const t = useTranslations('agentKnowledge')
   const { facts, factsActiveTotal } = competence
   const kindLabel = (k: FactKind) =>
     k === 'fact' ? t('kind_fact') : k === 'preference' ? t('kind_preference') : k === 'pattern' ? t('kind_pattern') : t('kind_correction')