feat(storage): migrate config, dedup and delivery state to D1

- Move oversized queue payloads from KV to R2 (PAYLOAD binding, webhooks/YYYY/MM/DD/*.json, KV queue:payload:* fallback)
- Persist routes/groups to D1 (d1_routes/d1_groups) with memory -> KV -> D1 three-tier cache, seeded from legacy KV config keys
- Move webhook dedup (dedup_keys), delivery state (delivery_state) and message tracking (message_tracking) to D1 via canUseD1 probe with automatic KV fallback
- Batch send_logs inserts (recordSendBatch) and add group_id/ts index
- Add storage-prune scheduled task for expired dedup/state/tracking rows
- Add TTL to invite:group:{id} index and audit all ephemeral KV keys
- Add D1 indexes for the new tables
- Sync AGENTS.md, README.md/zh and docs/ (en/zh) with the new storage layout

migrations/0006_config_d1.sql

@@ -0,0 +1,28 @@
+CREATE TABLE IF NOT EXISTS d1_groups (
+  id TEXT PRIMARY KEY,
+  name TEXT NOT NULL,
+  data TEXT NOT NULL,
+  version INTEGER NOT NULL DEFAULT 1,
+  created_at INTEGER NOT NULL,
+  updated_at INTEGER NOT NULL
+);
+
+CREATE TABLE IF NOT EXISTS d1_routes (
+  id TEXT NOT NULL,
+  group_id TEXT NOT NULL,
+  name TEXT NOT NULL,
+  enabled INTEGER NOT NULL DEFAULT 1,
+  filters TEXT NOT NULL,
+  targets TEXT NOT NULL,
+  stop INTEGER NOT NULL DEFAULT 0,
+  fallback INTEGER NOT NULL DEFAULT 0,
+  discord_role_ids TEXT,
+  ast TEXT,
+  version INTEGER NOT NULL DEFAULT 1,
+  created_at INTEGER NOT NULL,
+  updated_at INTEGER NOT NULL,
+  PRIMARY KEY (id, group_id),
+  FOREIGN KEY (group_id) REFERENCES d1_groups(id) ON DELETE CASCADE
+);
+
+CREATE INDEX IF NOT EXISTS idx_d1_routes_group_id ON d1_routes(group_id);