Add NOK pricing catalog, credit ledger, success-based charging, and tier-gated model routing

- PricingCatalog.php: single source of truth for plans (free/plus/pro), top-ups,
  Stripe price env keys, tool costs (0–6 credits), STT variable billing, feature limits
- FreeTier.php: monthly-first credit deduction, ledger (user_tool_credit_ledger),
  STT reservation/settle/release, monthly reset, trial logic
- StripeClient.php: canonical SKUs (plus/pro/topup_100/300/1000), legacy aliases kept
- stripe-checkout.php: subscription vs payment mode, trial gating, catalog metadata
- stripe-webhook.php: idempotent via stripe_events, handles subscription lifecycle +
  invoice.paid renewal + one-time topup credit grants
- All API tools: success-based credit deduction (check before, charge after)
- transcribe.php: file-size heuristic reservation, settle from actual provider duration
- ask.php + LegalTools.php: ToolModels engine resolution — Pro gets gpt-4o
- KorrespondAgent.php + korrespond.php: tier-gated draft deployment —
  Free/Plus gets gpt-4o-mini, Pro gets gpt-4o
- pricing.php: NOK-only, plan cards, top-up packs, Organisation contact card,
  tool cost table, separate monthly/prepaid balance display
- 003_pricing_credit_catalog.sql: ledger and STT reservation tables

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

includes/KorrespondAgent.php

@@ -234,8 +234,9 @@ PROMPT;
      *
      * @return array  Final result payload (matches NDJSON 'final' event shape).
      */
-    public function generate(array $intake, array $classify, ?callable $emit = null): array
+    public function generate(array $intake, array $classify, ?callable $emit = null, string $engine = 'azure_mini'): array
     {
+        $draftDeployment = ($engine === 'azure_full') ? 'gpt-4o' : 'gpt-4o-mini';
         $body         = $intake['recipient_body'] ?? 'other';
         $outputType   = $intake['output_type'] ?? 'email';
         $tone         = $intake['tone'] ?? 'neutral';
@@ -256,7 +257,7 @@ PROMPT;
         // ── Draft in Norwegian bokmål ───────────────────────────────────────────
         if ($emit) { $emit('progress', ['detail' => self::L('drafting_no', $userLang)]); }
         $draftNo = $this->draftNorwegian(
-            $intake, $classify, $retrieval['sources'], $bodyLabel, $outputType, $tone, $goal
+            $intake, $classify, $retrieval['sources'], $bodyLabel, $outputType, $tone, $goal, $draftDeployment
         );
 
         // ── Self-check: verify citations, deadline, goal, tone ──────────────────
@@ -528,7 +529,7 @@ PROMPT;
 
     private function draftNorwegian(
         array $intake, array $classify, array $sources, string $bodyLabel,
-        string $outputType, string $tone, string $goal
+        string $outputType, string $tone, string $goal, string $draftDeployment = self::DRAFT_DEPLOYMENT
     ): string {
         $context     = $this->buildContextBlob($intake);
         $toneLabel   = $this->toneLabelNorsk($tone);
@@ -576,7 +577,7 @@ Skriv kun utkastet. Ingen forklaring eller preamble. Bruk linjeskift som passer
 PROMPT;
 
         try {
-            return $this->azure->withDeployment(self::DRAFT_DEPLOYMENT)->chatText([
+            return $this->azure->withDeployment($draftDeployment)->chatText([
                 ['role' => 'system', 'content' => 'Du er en erfaren norsk juridisk forfatter som skriver presist og faktabasert.'],
                 ['role' => 'user',   'content' => $prompt],
             ], [