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/ZHAOXINKaiXianKX-U6780A/lscpu.txt

@@ -0,0 +1,25 @@
+Architecture:        x86_64
+CPU op-mode(s):      32-bit, 64-bit
+Byte Order:          Little Endian
+Address sizes:       40 bits physical, 48 bits virtual
+CPU(s):              8
+On-line CPU(s) list: 0-7
+Thread(s) per core:  1
+Core(s) per socket:  8
+Socket(s):           1
+NUMA node(s):        1
+Vendor ID:           CentaurHauls
+CPU family:          7
+Model:               59
+Model name:          ZHAOXIN KaiXian KX-U6780A@2.7GHz
+Stepping:            1
+CPU MHz:             2700.000
+CPU max MHz:         2700.0000
+CPU min MHz:         1200.0000
+BogoMIPS:            5389.32
+Virtualization:      VT-x
+L1d cache:           32K
+L1i cache:           32K
+L2 cache:            4096K
+NUMA node0 CPU(s):   0-7
+Flags:               fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx pdpe1gb rdtscp lm constant_tsc arch_perfmon rep_good nopl xtopology nonstop_tsc cpuid pni pclmulqdq monitor vmx smx est tm2 ssse3 cx16 xtpr pcid sse4_1 sse4_2 movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand rng rng_en ccs ccs_en ace ace_en ace2 phe phe_en pmm pmm_en parallax rng2 rng2_en phe2 phe2_en xmodx xmodx_en lahf_lm abm 3dnowprefetch invpcid_single ibrs ibpb tpr_shadow vnmi ept vpid fsgsbase tsc_adjust bmi1 smep bmi2 invpcid rdseed adx sha_ni xsaveopt dtherm ida umip arch_capabilities