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>

benchmark-data/data/hardware/VIANanoX2C4350AL/catproc.txt

@@ -0,0 +1,24 @@
+processor	: 0
+vendor_id	: CentaurHauls
+cpu family	: 6
+model		: 15
+model name	: VIA Nano X2 C4350AL @ 1.6+ GHz
+stepping	: 13
+cpu MHz		: 1729.000
+cache size	: 1024 KB
+physical id	: 0
+siblings	: 2
+core id		: 0
+cpu cores	: 1
+apicid		: 0
+initial apicid	: 0
+fpu		: yes
+fpu_exception	: yes
+cpuid level	: 10
+wp		: yes
+flags		: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat clflush acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx lm constant_tsc rep_good nopl pni monitor vmx est tm2 ssse3 cx16 xtpr sse4_1 popcnt rng rng_en ace ace_en ace2 phe phe_en pmm pmm_en lahf_lm ida
+bogomips	: 3466.79
+clflush size	: 64
+cache_alignment	: 128
+address sizes	: 36 bits physical, 48 bits virtual
+power management:

benchmark-data/data/hardware/VIANanoX2C4350AL/lscpu.txt

@@ -0,0 +1,20 @@
+Architecture:          x86_64
+CPU 运行模式：    32-bit, 64-bit
+Byte Order:            Little Endian
+CPU(s):                2
+On-line CPU(s) list:   0,1
+每个核的线程数：2
+每个座的核数：  1
+Socket(s):             1
+NUMA 节点：         1
+厂商 ID：           CentaurHauls
+CPU 系列：          6
+型号：              15
+Model name:            VIA Nano X2 C4350AL @ 1.6+ GHz
+步进：              13
+CPU MHz：             1729.000
+CPU max MHz:           1729.0000
+CPU min MHz:           1064.0000
+BogoMIPS:              3466.79
+虚拟化：           VT-x
+NUMA node0 CPU(s):     0,1