Phase 1: chunk store, tile rendering pipeline, and Leaflet viewer

api: WS gateway with token auth (Postgres-backed servers table, seeded via
`bun run seed`), column-granularity chunk store (hand-written SQL
migrations, no drizzle-kit CLI — its config loader needs esbuild, which
doesn't install cleanly here), dirty-chunk Redis stream producer with
per-flush dedup, and a tile-serving route.

worker: consumes the dirty-chunk stream via a proper consumer group,
rasterizes each chunk's columns into a single-resolution top-down PNG
(static pre-Flattening block-id palette), uploads to MinIO, and upserts
the tile pointer.

frontend: barebones Leaflet 2D viewer (CRS.Simple, one native zoom level)
wired to /api/servers and /api/tiles.

Object storage: tiles live in a dedicated `mcmapper-tiles` bucket on the
existing shared MinIO instance (devstack-minio on octo-winsrv) instead of
a per-stack container, via a scoped access key limited to that one bucket
— see README's "Object storage" section. MINIO_SECRET_KEY is real and is
deliberately not committed; docker-compose layers an untracked .env over
.env.example for it.

Full pipeline verified end-to-end against live containers: WS auth ->
Postgres upsert -> deduped Redis dirty-chunk event -> worker rasterize ->
MinIO upload -> tile fetch through the api route, including from the
actual mod-side WS client (see MCMapper-Mod's matching commit).

api/drizzle/0000_init.sql

@@ -0,0 +1,37 @@
+CREATE TABLE IF NOT EXISTS "servers" (
+	"id" uuid PRIMARY KEY DEFAULT gen_random_uuid() NOT NULL,
+	"name" text NOT NULL,
+	"token" text NOT NULL UNIQUE,
+	"auth_mode" text NOT NULL DEFAULT 'offline',
+	"created_at" timestamptz NOT NULL DEFAULT now()
+);
+
+CREATE TABLE IF NOT EXISTS "chunk_columns" (
+	"server_id" uuid NOT NULL REFERENCES "servers"("id") ON DELETE CASCADE,
+	"dimension" integer NOT NULL,
+	"x" integer NOT NULL,
+	"z" integer NOT NULL,
+	"block_id" integer NOT NULL,
+	"block_meta" integer NOT NULL,
+	"height" smallint NOT NULL,
+	"updated_at" timestamptz NOT NULL DEFAULT now(),
+	PRIMARY KEY ("server_id", "dimension", "x", "z")
+);
+
+CREATE TABLE IF NOT EXISTS "tile_pointers" (
+	"server_id" uuid NOT NULL REFERENCES "servers"("id") ON DELETE CASCADE,
+	"dimension" integer NOT NULL,
+	"zoom" integer NOT NULL DEFAULT 0,
+	"tile_x" integer NOT NULL,
+	"tile_z" integer NOT NULL,
+	"storage_key" text NOT NULL,
+	"content_hash" text NOT NULL,
+	"rendered_at" timestamptz NOT NULL DEFAULT now(),
+	PRIMARY KEY ("server_id", "dimension", "zoom", "tile_x", "tile_z")
+);
+
+-- Chunk-granularity lookup: a live delta touches individual columns, but the worker re-renders
+-- a whole chunk's 16x16 columns at once, keyed by floor(x/16), floor(z/16).
+CREATE INDEX IF NOT EXISTS "chunk_columns_chunk_idx" ON "chunk_columns" (
+	"server_id", "dimension", (floor("x" / 16.0)), (floor("z" / 16.0))
+);