feat(server): replay upload + fetch endpoints

API surface for the web replay viewer to come:

- `POST /api/replays`        — auth required; persists the JSON body
  verbatim, mints a server-side UUID, returns `{id}`. Three columns
  (final_score, time_seconds, recorded_at) are projected out of the
  payload at insert time so list endpoints don't have to scan blobs.
- `GET  /api/replays/recent` — public; returns the N most-recent
  replays across users (limit defaults to 20, capped at 50). Joins
  the username so the feed reads as "AliceWon · 2:14 win".
- `GET  /api/replays/:id`    — public; returns the full replay JSON
  the desktop client uploaded.

Migration `002_replays.sql` adds the `replays` table with indexes
on `received_at DESC` (recent feed) and `user_id` (per-user views).

Schema-version compatibility is the playback side's responsibility,
matching the desktop's existing `schema_version` gate — the server
just stores and serves whatever JSON came in.

`AppError::NotFound` added so `GET /api/replays/:id` can return a
proper 404 instead of an internal-server-error.

`.sqlx` cache regenerated for the new `query!` invocations.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.sqlx/query-3a9bd2e51b2389da5b7e85f26806fcffa896748e0b589d216cf60827fc3857a9.json

@@ -0,0 +1,68 @@
+{
+  "db_name": "SQLite",
+  "query": "SELECT\n              r.id              AS \"id!: String\",\n              u.username        AS \"username!: String\",\n              r.seed            AS \"seed!: i64\",\n              r.draw_mode       AS \"draw_mode!: String\",\n              r.mode            AS \"mode!: String\",\n              r.time_seconds    AS \"time_seconds!: i64\",\n              r.final_score     AS \"final_score!: i64\",\n              r.recorded_at     AS \"recorded_at!: String\",\n              r.received_at     AS \"received_at!: String\"\n           FROM replays r\n           JOIN users   u ON u.id = r.user_id\n           ORDER BY r.received_at DESC\n           LIMIT ?",
+  "describe": {
+    "columns": [
+      {
+        "name": "id!: String",
+        "ordinal": 0,
+        "type_info": "Text"
+      },
+      {
+        "name": "username!: String",
+        "ordinal": 1,
+        "type_info": "Text"
+      },
+      {
+        "name": "seed!: i64",
+        "ordinal": 2,
+        "type_info": "Integer"
+      },
+      {
+        "name": "draw_mode!: String",
+        "ordinal": 3,
+        "type_info": "Text"
+      },
+      {
+        "name": "mode!: String",
+        "ordinal": 4,
+        "type_info": "Text"
+      },
+      {
+        "name": "time_seconds!: i64",
+        "ordinal": 5,
+        "type_info": "Integer"
+      },
+      {
+        "name": "final_score!: i64",
+        "ordinal": 6,
+        "type_info": "Integer"
+      },
+      {
+        "name": "recorded_at!: String",
+        "ordinal": 7,
+        "type_info": "Text"
+      },
+      {
+        "name": "received_at!: String",
+        "ordinal": 8,
+        "type_info": "Text"
+      }
+    ],
+    "parameters": {
+      "Right": 1
+    },
+    "nullable": [
+      true,
+      false,
+      false,
+      false,
+      false,
+      false,
+      false,
+      false,
+      false
+    ]
+  },
+  "hash": "3a9bd2e51b2389da5b7e85f26806fcffa896748e0b589d216cf60827fc3857a9"
+}

.sqlx/query-5bc1984044bc792c2e9577a159ca22789469df14cb25144451f37e8cdad8165c.json

@@ -0,0 +1,20 @@
+{
+  "db_name": "SQLite",
+  "query": "SELECT replay_json FROM replays WHERE id = ?",
+  "describe": {
+    "columns": [
+      {
+        "name": "replay_json",
+        "ordinal": 0,
+        "type_info": "Text"
+      }
+    ],
+    "parameters": {
+      "Right": 1
+    },
+    "nullable": [
+      false
+    ]
+  },
+  "hash": "5bc1984044bc792c2e9577a159ca22789469df14cb25144451f37e8cdad8165c"
+}

.sqlx/query-6a36a96faa9d9b423aae3b72b0c049a1489b67ca2361581b2300bb4ee0bc9e2f.json

@@ -0,0 +1,12 @@
+{
+  "db_name": "SQLite",
+  "query": "INSERT INTO replays (\n              id, user_id, seed, draw_mode, mode, time_seconds, final_score,\n              recorded_at, received_at, replay_json\n           ) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)",
+  "describe": {
+    "columns": [],
+    "parameters": {
+      "Right": 10
+    },
+    "nullable": []
+  },
+  "hash": "6a36a96faa9d9b423aae3b72b0c049a1489b67ca2361581b2300bb4ee0bc9e2f"
+}