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/cards.ts

@@ -0,0 +1,146 @@
+import { v } from "convex/values";
+import { query, mutation } from "./_generated/server";
+
+// Get all cards (for local caching)
+export const list = query({
+  args: {},
+  handler: async (ctx) => {
+    return await ctx.db.query("cards").collect();
+  },
+});
+
+// Get cards updated after a timestamp (for incremental sync)
+export const listUpdatedAfter = query({
+  args: { since: v.number() },
+  handler: async (ctx, { since }) => {
+    return await ctx.db
+      .query("cards")
+      .withIndex("by_updated", (q) => q.gt("updatedAt", since))
+      .collect();
+  },
+});
+
+// Get a single card by Scryfall ID
+export const getByScryfallId = query({
+  args: { scryfallId: v.string() },
+  handler: async (ctx, { scryfallId }) => {
+    return await ctx.db
+      .query("cards")
+      .withIndex("by_scryfall", (q) => q.eq("scryfallId", scryfallId))
+      .first();
+  },
+});
+
+// Get cards by oracle ID (all printings of a card)
+export const getByOracleId = query({
+  args: { oracleId: v.string() },
+  handler: async (ctx, { oracleId }) => {
+    return await ctx.db
+      .query("cards")
+      .withIndex("by_oracle", (q) => q.eq("oracleId", oracleId))
+      .collect();
+  },
+});
+
+// Search cards by name
+export const searchByName = query({
+  args: { name: v.string() },
+  handler: async (ctx, { name }) => {
+    const cards = await ctx.db.query("cards").collect();
+    const lowerName = name.toLowerCase();
+    return cards.filter((card) =>
+      card.name.toLowerCase().includes(lowerName)
+    );
+  },
+});
+
+// Get total card count
+export const count = query({
+  args: {},
+  handler: async (ctx) => {
+    const cards = await ctx.db.query("cards").collect();
+    return cards.length;
+  },
+});
+
+// Insert a card (used by migration script)
+export const insert = mutation({
+  args: {
+    scryfallId: v.string(),
+    oracleId: v.string(),
+    name: v.string(),
+    setCode: v.string(),
+    collectorNumber: v.string(),
+    rarity: v.string(),
+    artist: v.optional(v.string()),
+    imageUri: v.optional(v.string()),
+    hash: v.bytes(),
+    hashVersion: v.number(),
+  },
+  handler: async (ctx, args) => {
+    // Check if card already exists
+    const existing = await ctx.db
+      .query("cards")
+      .withIndex("by_scryfall", (q) => q.eq("scryfallId", args.scryfallId))
+      .first();
+
+    if (existing) {
+      // Update existing card
+      await ctx.db.patch(existing._id, {
+        ...args,
+        updatedAt: Date.now(),
+      });
+      return existing._id;
+    }
+
+    // Insert new card
+    return await ctx.db.insert("cards", {
+      ...args,
+      updatedAt: Date.now(),
+    });
+  },
+});
+
+// Batch insert cards
+export const insertBatch = mutation({
+  args: {
+    cards: v.array(
+      v.object({
+        scryfallId: v.string(),
+        oracleId: v.string(),
+        name: v.string(),
+        setCode: v.string(),
+        collectorNumber: v.string(),
+        rarity: v.string(),
+        artist: v.optional(v.string()),
+        imageUri: v.optional(v.string()),
+        hash: v.bytes(),
+        hashVersion: v.number(),
+      })
+    ),
+  },
+  handler: async (ctx, { cards }) => {
+    const results = [];
+    for (const card of cards) {
+      const existing = await ctx.db
+        .query("cards")
+        .withIndex("by_scryfall", (q) => q.eq("scryfallId", card.scryfallId))
+        .first();
+
+      if (existing) {
+        await ctx.db.patch(existing._id, {
+          ...card,
+          updatedAt: Date.now(),
+        });
+        results.push(existing._id);
+      } else {
+        const id = await ctx.db.insert("cards", {
+          ...card,
+          updatedAt: Date.now(),
+        });
+        results.push(id);
+      }
+    }
+    return results;
+  },
+});