Migrate from .NET MAUI to Expo + Convex

Complete rewrite of Scry using TypeScript stack:

- Expo/React Native with Expo Router (file-based routing)
- Convex backend (serverless functions + real-time database)
- Adaptive camera system (expo-camera in Expo Go, Vision Camera in production)
- React Native Skia + fast-opencv for image processing
- GDPR-compliant auth setup with Zitadel OIDC (pending configuration)

Key features:
- Card recognition pipeline ported to TypeScript
- Perceptual hashing (192-bit color pHash)
- CLAHE preprocessing for lighting normalization
- Local SQLite cache with Convex sync
- Collection management with offline support

Removes all .NET/MAUI code (src/, test/, tools/).

💘 Generated with Crush

Assisted-by: Claude Opus 4.5 via Crush <crush@charm.land>

convex/collections.ts

@@ -0,0 +1,166 @@
+import { v } from "convex/values";
+import { query, mutation } from "./_generated/server";
+
+// Get user's collection (alias for backwards compat)
+export const getByUser = query({
+  args: { userId: v.id("users") },
+  handler: async (ctx, { userId }) => {
+    const entries = await ctx.db
+      .query("collections")
+      .withIndex("by_user", (q) => q.eq("userId", userId))
+      .collect();
+
+    // Enrich with card data
+    const enriched = await Promise.all(
+      entries.map(async (entry) => {
+        const card = await ctx.db.get(entry.cardId);
+        return {
+          ...entry,
+          card,
+        };
+      })
+    );
+
+    return enriched.filter((e) => e.card !== null);
+  },
+});
+
+// Get user's collection
+export const getMyCollection = query({
+  args: { userId: v.id("users") },
+  handler: async (ctx, { userId }) => {
+    const entries = await ctx.db
+      .query("collections")
+      .withIndex("by_user", (q) => q.eq("userId", userId))
+      .collect();
+
+    // Enrich with card data
+    const enriched = await Promise.all(
+      entries.map(async (entry) => {
+        const card = await ctx.db.get(entry.cardId);
+        return {
+          ...entry,
+          card,
+        };
+      })
+    );
+
+    return enriched.filter((e) => e.card !== null);
+  },
+});
+
+// Get collection stats
+export const getStats = query({
+  args: { userId: v.id("users") },
+  handler: async (ctx, { userId }) => {
+    const entries = await ctx.db
+      .query("collections")
+      .withIndex("by_user", (q) => q.eq("userId", userId))
+      .collect();
+
+    const totalCards = entries.reduce((sum, e) => sum + e.quantity, 0);
+    const uniqueCards = entries.length;
+    const foilCount = entries.filter((e) => e.isFoil).length;
+
+    return {
+      totalCards,
+      uniqueCards,
+      foilCount,
+    };
+  },
+});
+
+// Add card to collection
+export const addCard = mutation({
+  args: {
+    userId: v.id("users"),
+    cardId: v.id("cards"),
+    quantity: v.number(),
+    isFoil: v.boolean(),
+  },
+  handler: async (ctx, { userId, cardId, quantity, isFoil }) => {
+    // Check if entry already exists
+    const existing = await ctx.db
+      .query("collections")
+      .withIndex("by_user_card", (q) =>
+        q.eq("userId", userId).eq("cardId", cardId).eq("isFoil", isFoil)
+      )
+      .first();
+
+    if (existing) {
+      // Update quantity
+      await ctx.db.patch(existing._id, {
+        quantity: existing.quantity + quantity,
+      });
+      return existing._id;
+    }
+
+    // Create new entry
+    return await ctx.db.insert("collections", {
+      userId,
+      cardId,
+      quantity,
+      isFoil,
+      addedAt: Date.now(),
+    });
+  },
+});
+
+// Alias for addCard
+export const add = addCard;
+
+// Update card quantity
+export const updateQuantity = mutation({
+  args: {
+    entryId: v.id("collections"),
+    quantity: v.number(),
+  },
+  handler: async (ctx, { entryId, quantity }) => {
+    if (quantity <= 0) {
+      await ctx.db.delete(entryId);
+      return null;
+    }
+    await ctx.db.patch(entryId, { quantity });
+    return entryId;
+  },
+});
+
+// Remove card from collection
+export const removeCard = mutation({
+  args: { entryId: v.id("collections") },
+  handler: async (ctx, { entryId }) => {
+    await ctx.db.delete(entryId);
+  },
+});
+
+// Alias for removeCard
+export const remove = removeCard;
+
+// Decrease quantity by 1
+export const decrementQuantity = mutation({
+  args: { entryId: v.id("collections") },
+  handler: async (ctx, { entryId }) => {
+    const entry = await ctx.db.get(entryId);
+    if (!entry) return null;
+
+    if (entry.quantity <= 1) {
+      await ctx.db.delete(entryId);
+      return null;
+    }
+
+    await ctx.db.patch(entryId, { quantity: entry.quantity - 1 });
+    return entryId;
+  },
+});
+
+// Increase quantity by 1
+export const incrementQuantity = mutation({
+  args: { entryId: v.id("collections") },
+  handler: async (ctx, { entryId }) => {
+    const entry = await ctx.db.get(entryId);
+    if (!entry) return null;
+
+    await ctx.db.patch(entryId, { quantity: entry.quantity + 1 });
+    return entryId;
+  },
+});