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/2xAMDOpteron6238/catproc.txt

@@ -0,0 +1,25 @@
+processor	: 0
+vendor_id	: AuthenticAMD
+cpu family	: 21
+model		: 1
+model name	: AMD Opteron(TM) Processor 6238                 
+stepping	: 2
+cpu MHz		: 2600.148
+cache size	: 2048 KB
+physical id	: 0
+siblings	: 12
+core id		: 0
+cpu cores	: 6
+apicid		: 32
+initial apicid	: 0
+fpu		: yes
+fpu_exception	: yes
+cpuid level	: 13
+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 ht syscall nx mmxext fxsr_opt pdpe1gb rdtscp lm constant_tsc rep_good nonstop_tsc extd_apicid amd_dcm aperfmperf pni pclmulqdq monitor ssse3 cx16 sse4_1 sse4_2 popcnt aes xsave avx lahf_lm cmp_legacy svm extapic cr8_legacy abm sse4a misalignsse 3dnowprefetch osvw ibs xop skinit wdt lwp fma4 nodeid_msr topoext perfctr_core cpb npt lbrv svm_lock nrip_save tsc_scale vmcb_clean flushbyasid decodeassists pausefilter pfthreshold
+bogomips	: 5200.29
+TLB size	: 1536 4K pages
+clflush size	: 64
+cache_alignment	: 64
+address sizes	: 48 bits physical, 48 bits virtual
+power management: ts ttp tm 100mhzsteps hwpstate cpb