Instructions per chat (system prompt addition; UI dialog and Telegram /prompt)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

web/src/i18n/en.ts

@@ -592,6 +592,11 @@ export const en = {
   "chat.compactingAuto": "Context nearly full – compacting the conversation automatically",
   "chat.compactingManual": "Compacting the conversation",
   "chat.compactingDetail": "{tokens} of {limit} tokens ({pct}) – the agent continues with a summary afterwards",
+  "instructions.title": "Instructions for this chat",
+  "instructions.hint": "Apply to every message in this chat, in addition to the mode – e.g. language, tone, rules, the part of the project to work on.",
+  "instructions.placeholder": "e.g. Always answer in English. Only change files under api/. Ask before adding dependencies.",
+  "instructions.clear": "Remove",
+  "instructions.chip": "Instructions",
   "chat.compacted": "Conversation compacted – summary",
   "chat.context": "Context",
   "chat.contextHint": "{tokens} tokens in the last request",