[rahul05ranjan]

Fixes #11

Adds a Bengali locale: piscout/static/locales/bn.json, locale file only — no code changed.

What's translated

• All 167 UI strings (ui.exact 56, ui.sub 98, ui.rx 13) — every visible screen (device list, connect, flash, re-image, terminal/remote desktop, health check, update prompts).
• backend is intentionally left empty so those messages fall back to English (the guide's recommended "partial file" shape); a later PR can translate them.
• installer section skipped (optional per the guide).
• rx entries keep pattern byte-identical to en.json; only replace is written. $1-style captures and the {{2}} recursion are preserved.

How I verified

• python tools/i18n_check.py → bn.json: 167/300 translated, 0 error(s) (placeholder/pattern checks all pass).
• Ran the real frontend translation engine (piscout/static/i18n.js) under Node with window.PISCOUT_LOCALES loaded from the actual locales directory and piscout_lang = bn, i.e. exactly what a Bengali browser does:
  • exact matches: 裝置 → ডিভাইস, SSH 未開 → SSH বন্ধ;
  • sub matches: 正在掃描區網… → নেটওয়ার্ক স্ক্যান হচ্ছে…, the file-drop hint, the update notice;
  • rx captures: scan line → · 12 টি ডিভাইস পাওয়া গেছে, এর মধ্যে 3 টি রাস্পবেরি পাই…, uptime → 2 দিন 5 ঘণ্টা 40 মিনিট, batch confirm → 4 টি ডিভাইসে «রিবুট» চালাবেন? — the {{2}} recursion even re-translated the captured action name 重新開機 through the exact table (রিবুট), so the engine round-trips my rules end to end.
• One parity note, recorded rather than fixed (per the guide: no app-code changes in a locale PR): the wipe-confirm line 確定清除磁碟 3 並燒錄 comes out as 確定清除ডিস্ক 3 並燒錄 because the unanchored 磁碟 (\d+) rx rule fires before the anchored wipe rule — English shows the same artifact (確定清除Disk 3 並燒錄), verified by running the engine with en. The bn file behaves identically to en here; fixing the rule order in i18n.js would be a separate small code change if you want it.
• Bengali numerals: I kept Latin digits for counts that come from $1 captures (device counts, disk numbers) since they mirror the live data, and used Bengali digits only in fixed prose (১০–৩০ মিনিট).
• Not run: the GUI preview (PISCOUT_DEMO=1 python run_gui.py) — my dev host is headless, so I could not eyeball Devanagari/Bengali text fitting in buttons. The i18n checker and the real translation engine were the verification path; if any label clips on screen, tell me and I'll shorten that string.

File: piscout/static/locales/bn.json only.