feat(ai): services partages A2 + SSE streaming B4 + confirmations UI B5 (#79)

frontend/locales/en.json

@@ -86,6 +86,8 @@
   "ai.action_created_dir": "Folder created: {path}",
   "ai.action_created_file": "File created: {path}",
   "ai.action_failed": "Action failed: {error}",
+  "ai.agent_mode_off": "Agent mode off (read/search + actions)",
+  "ai.agent_mode_on": "Agent mode on (read/search tools + actions)",
   "ai.casual": "Casual tone",
   "ai.close": "Close assistant",
   "ai.completion_added": "AI: completion added",
@@ -94,6 +96,7 @@
   "ai.context_general_desc": "Questions about the app and file creation",
   "ai.continue": "Continue",
   "ai.custom_rewrite": "Custom rewrite",
+  "ai.diff_preview": "Change preview",
   "ai.done": "AI: text processed",
   "ai.edit": "Edit",
   "ai.error_invalid_key": "Invalid API key",
@@ -149,6 +152,8 @@
   "ai.to_list": "Convert to list",
   "ai.to_table": "Convert to table",
   "ai.tone_hint": "Changes the text tone",
+  "ai.tool_call": "Tool: {name}",
+  "ai.tool_call_failed": "Tool {name} failed",
   "ai.toolbar_edit": "Edit",
   "ai.toolbar_generate": "Generate",
   "ai.toolbar_rewrite": "Rewrite",
@@ -1212,6 +1217,7 @@
   "help.assistant_markdown": "Formatted answers: headings, lists, tables, quotes and code blocks.",
   "help.assistant_links": "Cited files and paths are links: click a file to open it, a folder to reveal it in the tree.",
   "help.assistant_sessions": "The header history icon lists past sessions (reopen or delete); “+” starts a new conversation.",
+  "help.assistant_agent": "The \"agent mode\" button enables tools (read, list, search); modifying actions require confirmation with a change preview.",
   "help.toolbar_section": "AI toolbar",
   "help.tree_section": "Vault tree",
   "help.use_cases": "Use cases",