feat: Implement card pool depletion handling and wildcard rarity fallback for pack generation

docs/development/devlog/2025-12-17-140000_fix_expansion_generation.md

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+# Fix Expansion Pack Generation (Infinite Cards)
+
+## Problem
+The user reported two issues with "From Expansion" pack generation:
+1. Incorrect amount of packs generated (e.g., 10 instead of 36).
+2. The generator was using a finite pool of cards (like a custom cube) instead of an infinite supply (like opening fresh packs).
+
+## Root Cause
+The `PackGeneratorService` defaults to generating packs without replacement (`withReplacement: false`). This means once a card is used, it is removed from the pool.
+For a standard set (Expansion), the pool contains only one copy of each card (from Scryfall fetch).
+When generating a large number of packs (e.g., 36 for a box), the rare/mythic/uncommon pools would deplete quickly, causing the generator to stop early and produce fewer packs than requested.
+
+## Solution
+Modified `src/server/index.ts` to enforce `settings.withReplacement = true` when `sourceMode === 'set'`.
+This ensures that:
+- The pack generator refreshes the card pools for every new pack.
+- Generating 36 packs (or any number) is possible even from a single set of source cards.
+- Duplicates are allowed across packs (simulating a print run), while maintaining uniqueness within a single pack (handled by `buildSinglePack`).
+
+## Changes
+- **File**: `src/server/index.ts`
+- **Logic**: Added a check in the `/api/packs/generate` route to set `settings.withReplacement = true` if `sourceMode === 'set'`.