chore: pin all dependency versions for reproducible builds

Remove ^ prefix from all 33 dependencies across root, server, and
frontend package.json files. Lockfile regenerated and verified with
pnpm install --frozen-lockfile.

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

server/package.json

@@ -11,22 +11,22 @@
     "migrate": "tsx src/db/migrate.ts"
   },
   "dependencies": {
-    "@cashu/cashu-ts": "^3.5.0",
-    "@hono/node-server": "^1.14.1",
-    "better-sqlite3": "^11.9.1",
-    "chalk": "^5.6.2",
-    "dotenv": "^17.3.1",
-    "drizzle-orm": "^0.40.1",
-    "hono": "^4.7.6",
-    "nanoid": "^5.1.5",
-    "nostr-tools": "^2.23.3",
-    "zod": "^4.3.6"
+    "@cashu/cashu-ts": "3.5.0",
+    "@hono/node-server": "1.14.1",
+    "better-sqlite3": "11.9.1",
+    "chalk": "5.6.2",
+    "dotenv": "17.3.1",
+    "drizzle-orm": "0.40.1",
+    "hono": "4.7.6",
+    "nanoid": "5.1.5",
+    "nostr-tools": "2.23.3",
+    "zod": "4.3.6"
   },
   "devDependencies": {
-    "@types/better-sqlite3": "^7.6.13",
-    "@types/node": "^22.13.14",
-    "drizzle-kit": "^0.30.5",
-    "tsx": "^4.19.3",
-    "typescript": "^5.7.3"
+    "@types/better-sqlite3": "7.6.13",
+    "@types/node": "22.13.14",
+    "drizzle-kit": "0.30.5",
+    "tsx": "4.19.3",
+    "typescript": "5.7.3"
   }
 }