feat: 대역폭 추정 및 DAU 표시 기능 추가

- 동시접속자 기반 월간 대역폭 자동 추정
- DAU(일일활성사용자) 추정치 표시 (동접 × 10-14)
- 대역폭 기반 Linode/Vultr 자동 선택 로직
- 비용 분석에 대역폭 비용 포함
- 지역 미선택시 서울/도쿄/오사카/싱가포르 기본 표시
- 지역별 서버 분리 표시 (GROUP BY instance + region)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

vps-benchmark-schema.sql

@@ -0,0 +1,30 @@
+-- Real VPS Benchmark data schema
+-- Source: LowEndTalk community (Geekbench 5/6 results)
+
+CREATE TABLE IF NOT EXISTS vps_benchmarks (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    provider_name TEXT NOT NULL,
+    plan_name TEXT NOT NULL,
+    cpu_type TEXT, -- AMD, Intel
+    vcpu INTEGER,
+    memory_gb INTEGER,
+    country_code TEXT,
+    geekbench_single INTEGER,
+    geekbench_multi INTEGER,
+    geekbench_total INTEGER,
+    monthly_price_usd REAL,
+    performance_per_dollar REAL,
+    geekbench_version TEXT,
+    benchmark_url TEXT,
+    created_at TEXT DEFAULT CURRENT_TIMESTAMP
+);
+
+-- Unique constraint for deduplication (used by ON CONFLICT in scraper)
+CREATE UNIQUE INDEX IF NOT EXISTS idx_vps_benchmarks_unique
+ON vps_benchmarks(provider_name, plan_name, COALESCE(country_code, ''));
+
+-- Index for efficient queries
+CREATE INDEX IF NOT EXISTS idx_vps_benchmarks_provider ON vps_benchmarks(provider_name);
+CREATE INDEX IF NOT EXISTS idx_vps_benchmarks_vcpu ON vps_benchmarks(vcpu);
+CREATE INDEX IF NOT EXISTS idx_vps_benchmarks_price ON vps_benchmarks(monthly_price_usd);
+CREATE INDEX IF NOT EXISTS idx_vps_benchmarks_single ON vps_benchmarks(geekbench_single);