feat(openflare): migrate of_node_access_logs to ClickHouse

Move node access log storage from PostgreSQL/SQLite to ClickHouse
(database: openflare). System startup now requires a healthy ClickHouse
connection and auto-initializes the schema. Agent heartbeat writes access
logs via batch insert; goose migration drops the legacy relational table.

openflare-server/support-files/sql/create_clickhouse_openflare.sql

@@ -0,0 +1,38 @@
+CREATE DATABASE IF NOT EXISTS openflare;
+
+USE openflare;
+
+CREATE TABLE IF NOT EXISTS of_node_access_logs
+(
+    id          UInt64,
+    node_id     String,
+    logged_at   DateTime64(3, 'UTC'),
+    remote_addr String,
+    region      String,
+    host        String,
+    path        String,
+    status_code Int32,
+    created_at  DateTime64(3, 'UTC')
+)
+ENGINE = MergeTree()
+PARTITION BY toYYYYMM(logged_at)
+ORDER BY (node_id, logged_at, remote_addr, host, path, status_code)
+SETTINGS index_granularity = 8192;
+
+CREATE TABLE IF NOT EXISTS w_user_access_logs
+(
+    id          UInt64,
+    user_id     UInt64,
+    path        String,
+    method      String,
+    ip          String,
+    user_agent  String,
+    headers     String,
+    status      Int32,
+    latency     Int64,
+    created_at  DateTime
+)
+ENGINE = MergeTree()
+PARTITION BY toYYYYMM(created_at)
+ORDER BY (created_at, ip, user_id)
+SETTINGS index_granularity = 8192;