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/AMDAthlon643700/catproc.txt

@@ -0,0 +1,19 @@
+processor	: 0
+vendor_id	: AuthenticAMD
+cpu family	: 15
+model		: 39
+model name	: AMD Athlon(tm) 64 Processor 3700+
+stepping	: 1
+cpu MHz		: 2200.000
+cache size	: 1024 KB
+fpu		: yes
+fpu_exception	: yes
+cpuid level	: 1
+wp		: yes
+flags		: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 syscall nx mmxext fxsr_opt lm 3dnowext 3dnow up rep_good pni lahf_lm
+bogomips	: 4420.47
+TLB size	: 1024 4K pages
+clflush size	: 64
+cache_alignment	: 64
+address sizes	: 40 bits physical, 48 bits virtual
+power management: ts fid vid ttp tm stc

benchmark-data/data/hardware/AMDAthlon643700/lscpu.txt

@@ -0,0 +1,15 @@
+Architecture:          x86_64
+CPU op-mode(s):        64-bit
+CPU(s):                1
+Thread(s) per core:    1
+Core(s) per socket:    1
+CPU socket(s):         1
+NUMA node(s):          1
+Vendor ID:             AuthenticAMD
+CPU family:            15
+Model:                 39
+Stepping:              1
+CPU MHz:               2200.000
+L1d cache:             64K
+L1i cache:             64K
+L2 cache:              1024K