feat: comprehensive i18n coverage — all static text + auto-translate toasts

Locale files expanded to 300+ keys covering all sections:
- Header menu, sidebar, search, viewer, editor, AI toolbar
- Config modal (all sections), help modal, dashboard, graph, mermaid
- Context menus, offline UI, palette, auth, shares, backups
- All toasts and confirmations

Automatic data-i18n tagging in index.html (177 attributes)
via Python script — handles all user-facing static text nodes.
Zero concatenation errors verified.

i18n.js: added tr() reverse-lookup function
(French text → key → current locale translation)

ui.js: showToast() now auto-translates via tr()
— all 24 existing toast call sites benefit automatically

frontend/locales/en.json

@@ -10,6 +10,22 @@
   "header.refresh": "Refresh",
   "header.install_app": "Install app",
   "header.admin_panel": "Administration",
+  "header.menu_config": "Settings",
+  "header.menu_config_desc": "Application settings",
+  "header.menu_help": "User guide",
+  "header.menu_help_desc": "Open help",
+  "header.menu_about": "About",
+  "header.menu_about_desc": "Version, credits & info",
+  "header.menu_profile": "Profile",
+  "header.menu_profile_desc": "Language & preferences",
+  "header.menu_logout": "Sign out",
+  "header.menu_logout_desc": "End session",
+  "header.menu_admin": "Administration",
+  "header.menu_admin_desc": "Manage users",
+  "header.sync_status": "Sync",
+  "header.sidebar_toggle": "Toggle sidebar",
+  "header.menu_toggle": "Menu",
+  "header.quick_help": "Quick Help",
 
   "sidebar.filter_placeholder": "Filter files...",
   "sidebar.tab_vaults": "Vaults",
@@ -19,6 +35,20 @@
   "sidebar.loading": "Loading...",
   "sidebar.no_results": "No results",
   "sidebar.vault_context_all": "All vaults",
+  "sidebar.saved_searches_tab": "Searches",
+  "sidebar.saved_dirs_tab": "Folders",
+  "sidebar.no_saved_searches": "No saved searches",
+  "sidebar.no_recent_files": "No recent files",
+  "sidebar.case_sensitive": "Case sensitive",
+  "sidebar.clear_filter": "Clear",
+  "sidebar.filter_results_grouped": "Grouped results",
+  "sidebar.filter_instant": "Instant search",
+  "sidebar.expand_collapse": "Expand/Collapse",
+  "sidebar.open_file": "Open file",
+  "sidebar.file_icons": "Icons",
+  "sidebar.vault_specific": "Specific vault",
+  "sidebar.sidebar_dropdown": "Vault context menu",
+  "sidebar.sidebar_filtering": "Sidebar filtering",
 
   "search.operators_help": "Operators: tag:word, vault:name, title:word, path:word, ext:md",
   "search.results_count": "{count} result(s)",
@@ -35,6 +65,21 @@
   "search.case_sensitive": "Case sensitive",
   "search.whole_word": "Whole word",
   "search.regex": "Regular expression",
+  "search.dropdown_history": "History",
+  "search.dropdown_files": "Files",
+  "search.dropdown_clear_history": "Clear history",
+  "search.clear": "Clear",
+  "search.filter_path_title": "Path filters (Alt-F)",
+  "search.aria_label": "Search suggestions",
+  "search.sections_all_vaults": "All vaults",
+  "search.simple_search": "Simple search",
+  "search.full_text": "Search everywhere",
+  "search.smart_scoring": "Smart scoring",
+  "search.highlighted_snippets": "Highlighted snippets",
+  "search.pagination": "Pagination",
+  "search.advanced_operators": "Advanced operators",
+  "search.include_placeholder": "Include: **/*.md, notes/**",
+  "search.exclude_placeholder": "Exclude: vendor/*, *.lock",
 
   "viewer.source": "Source",
   "viewer.markdown": "Markdown",
@@ -52,6 +97,17 @@
   "viewer.binary_unsupported": "Unsupported binary file",
   "viewer.binary_download": "Download file",
   "viewer.pdf_pages": "{count} pages",
+  "viewer.on_this_page": "ON THIS PAGE",
+  "viewer.no_headings": "No headings in this document",
+  "viewer.metadata_tags": "Tags",
+  "viewer.metadata_created": "Created",
+  "viewer.metadata_modified": "Modified",
+  "viewer.metadata_size": "Size",
+  "viewer.metadata_vault": "Vault",
+  "viewer.metadata_path": "Path",
+  "viewer.breadcrumb_home": "Home",
+  "viewer.unsupported_file": "This file is binary and cannot be displayed",
+  "viewer.click_to_download": "Click to download",
 
   "editor.save": "Save",
   "editor.cancel": "Cancel",
@@ -64,6 +120,8 @@
   "editor.find_whole": "Whole word",
   "editor.no_results": "No results",
   "editor.close": "Close",
+  "editor.forge_help": "Forge editor help",
+  "editor.forge_close_editor": "Close editor / modal",
 
   "ai.toolbar_edit": "Edit",
   "ai.toolbar_tone": "Tone",
@@ -90,6 +148,8 @@
   "ai.no_api_key": "No API key configured",
   "ai.select_text": "Select text to process",
   "ai.done": "AI: text processed",
+  "ai.completion_added": "AI: completion added",
+  "ai.rewrite_done": "AI: text rewritten",
 
   "dashboard.welcome": "Welcome to ObsiGate",
   "dashboard.stats": "Statistics",
@@ -103,8 +163,22 @@
   "dashboard.no_bookmarks": "No bookmarks",
   "dashboard.no_conflicts": "No conflicts",
   "dashboard.no_recent": "No recent files",
+  "dashboard.no_shares": "No shared documents",
+  "dashboard.shares": "Shares",
 
   "config.title": "Settings",
+  "config.section_search": "Search settings",
+  "config.section_perf": "Performance",
+  "config.section_server": "Server",
+  "config.section_watcher": "Auto sync",
+  "config.section_profile": "User profile",
+  "config.section_ai": "AI API keys",
+  "config.section_hidden": "Hidden files",
+  "config.section_webhooks": "Webhooks",
+  "config.section_shares": "Public shares",
+  "config.section_backups": "Backups",
+  "config.section_diag": "Diagnostics",
+  "config.section_about": "About",
   "config.profile": "User profile",
   "config.profile_desc": "Personal preferences to customize your ObsiGate experience.",
   "config.lang_label": "Preferred language",
@@ -130,20 +204,213 @@
   "config.diagnostics_desc": "Technical information about the server state.",
   "config.reindex": "Reindex",
   "config.reindex_desc": "Rebuild the search index for all vaults.",
-  "config.client_config": "Client configuration",
-  "config.server_config": "Server configuration",
+  "config.client_config": "Client config",
+  "config.server_config": "Server config",
+  "config.restart_required": "Restart required",
+  "config.no_restart": "No restart needed",
+  "config.note": "Note:",
+  "config.test": "Test",
+  "config.debounce_label": "Debounce delay (ms)",
+  "config.results_per_page_label": "Results per page",
+  "config.min_query_label": "Min. query length",
+  "config.timeout_label": "Search timeout (ms)",
+  "config.max_backups_label": "Max backups per file",
+  "config.workers_label": "Search workers",
+  "config.max_content_label": "Max content size (bytes)",
+  "config.title_boost_label": "Title boost",
+  "config.tag_boost_label": "Tag boost",
+  "config.prefix_expansions_label": "Max prefix expansions",
+  "config.tag_filtering_label": "Tag filtering",
+  "config.watcher_enabled_label": "Enable watcher",
+  "config.watcher_polling_label": "Polling mode (fallback)",
+  "config.watcher_interval_label": "Polling interval (s)",
+  "config.watcher_debounce_label": "Debounce (s)",
+  "config.ai_deepseek_label": "DeepSeek API Key",
+  "config.ai_openrouter_label": "OpenRouter API Key",
+  "config.ai_gemini_label": "Gemini API Key",
+  "config.ai_default_provider": "Default provider",
+  "config.ai_model": "Model",
+  "config.save_ai_keys": "Save keys",
+  "config.save_backend": "Save server configuration",
+  "config.reset": "Reset",
+  "config.add_webhook": "Add",
+  "config.webhook_name_placeholder": "Name",
+  "config.webhook_url_placeholder": "URL",
+  "config.create_share": "Create share",
+  "config.shares_empty": "No active shares",
+  "config.hidden_include_label": "Include hidden files",
+  "config.hidden_whitelist_label": "Whitelist (comma-separated)",
+  "config.save_hidden": "Save",
 
   "help.title": "ObsiGate Help",
   "help.shortcuts": "Keyboard shortcuts",
   "help.search_operators": "Search operators",
   "help.markdown": "Markdown syntax",
   "help.about": "About",
+  "help.quick_help": "Quick Help",
+  "help.shortcut_palette": "Command palette",
+  "help.shortcut_palette_cmd": "Command palette (command mode)",
+  "help.shortcut_focus_search": "Focus search bar",
+  "help.shortcut_save": "Save",
+  "help.shortcut_close": "Close editor / modal",
+  "help.shortcut_forge_help": "Forge editor help",
+  "help.guide_official": "Official guide",
+  "help.experience": "Experience",
+  "help.simple": "Simple",
+  "help.instant": "Instant",
+  "help.multi_vault": "Multi-vault",
+  "help.header_section": "Header",
+  "help.hamburger_btn": "Hamburger menu button",
+  "help.sidebar_toggle_btn": "Sidebar toggle button",
+  "help.logo": "ObsiGate logo",
+  "help.search_bar": "Search bar",
+  "help.vault_indicator": "Vault indicator",
+  "help.menu_options": "Options menu",
+  "help.sidebar_section": "Sidebar",
+  "help.sidebar_tabs": "The sidebar has two tabs:",
+  "help.sidebar_features": "Sidebar features:",
+  "help.filtering": "Filtering",
+  "help.quick_select": "Quick select",
+  "help.resize": "Resize",
+  "help.hide": "Hide",
+  "help.content_area": "Content area",
+  "help.content_shows": "The main area displays:",
+  "help.breadcrumb": "Breadcrumb",
+  "help.title_tags": "Title and tags",
+  "help.action_buttons": "Action buttons",
+  "help.rendered_content": "Rendered content",
+  "help.tree_section": "Vault tree",
+  "help.sidebar_filtering": "Sidebar filtering",
+  "help.case_sensitive": "Case-sensitive",
+  "help.clear": "Clear",
+  "help.results_grouped": "Grouped results",
+  "help.breadcrumb_reposition": "Breadcrumb and repositioning",
+  "help.click_vault": "Click the vault",
+  "help.click_segment": "Click a segment",
+  "help.auto_scroll": "Auto-scroll",
+  "help.vault_selector": "Vault selector",
+  "help.menu_header": "Header menu",
+  "help.sidebar_dropdown": "Sidebar dropdown",
+  "help.all_vaults": "All vaults",
+  "help.vault_specific": "Specific vault",
+  "help.tabs_section": "Opening tabs",
+  "help.single_click": "Single click",
+  "help.double_click": "Double click",
+  "help.recent_nav": "Recent navigation",
+  "help.tab_nav": "Tab navigation",
+  "help.click_tab": "Click a tab",
+  "help.tab_features": "Features",
+  "help.tab_bar": "Tab bar",
+  "help.active_tab": "Active tab",
+  "help.preview_tab": "Preview",
+  "help.persistent_tabs": "Persistent tabs",
+  "help.simple_search": "Simple search",
+  "help.search_everywhere": "Search everywhere",
+  "help.smart_scoring": "Smart scoring",
+  "help.highlighted_snippets": "Highlighted snippets",
+  "help.pagination": "Pagination",
+  "help.advanced_operators": "Advanced operators",
+  "help.search_facets": "Facets",
+  "help.search_save": "Saved searches",
+  "help.search_history": "Search history",
+  "help.search_filters": "Search filters",
+  "help.mermaid_section": "Mermaid diagrams",
+  "help.rendering_md": "Rendering in Markdown",
+  "help.themes": "Themes",
+  "help.code_preview": "Code + Preview",
+  "help.zoom_pan": "Zoom & Pan",
+  "help.export": "Export",
+  "help.mermaid_templates": "Templates",
+  "help.theme_section": "Theme",
+  "help.theme_toggle": "Toggle between themes:",
+  "help.light": "Light",
+  "help.dark": "Dark",
+  "help.context_menu": "Context menu (right click)",
+  "help.context_actions": "File actions",
+  "help.new_file": "New file",
+  "help.new_folder": "New folder",
+  "help.rename": "Rename",
+  "help.delete": "Delete",
+  "help.copy_path": "Copy path",
+  "help.properties": "Properties",
+  "help.graph_view": "Graph view",
+  "help.find_in_page": "Find in page",
+  "help.find_capabilities": "Regex, whole word, case-sensitive search in the displayed document with DOM TreeWalker.",
+  "help.file_viewer": "File viewer",
+  "help.file_actions": "Actions on the open file:",
+  "help.actions_available": "Buttons available above the content:",
+  "help.actions_detail": "Buttons available above the content:",
+  "help.share_button": "Share button",
+  "help.popout_button": "Dedicated button",
+  "help.outline_panel": "Outline panel (right)",
+  "help.backlinks_panel": "Backlinks panel",
+  "help.fallback_editor": "Fallback editor",
+  "help.editor_section": "Editor",
+  "help.toolbar_section": "AI toolbar",
+  "help.ai_features": "Edit, tone, translate, generate and tools via AI.",
+  "help.security_section": "Security",
+  "help.audit_log": "Audit log",
+  "help.backup_auto": "Auto backup",
+  "help.atomic_writes": "Atomic writes",
+  "help.rate_limiting": "Rate limiting",
+  "help.secret_redaction": "Secret redaction",
+  "help.syncthing_conflicts": "Syncthing conflicts",
+  "help.before_write": "Before write",
+  "help.ci_cd": "CI/CD automation",
+  "help.pwa_section": "PWA",
+  "help.external_audit": "External audit",
+  "help.shortcut_prev_tab": "Previous tab",
+  "help.shortcut_next_tab": "Next tab",
+  "help.shortcut_close_tab": "Close tab",
+  "help.shortcut_close_palette": "Close palette",
+  "help.shortcut_select": "Open/select",
+  "help.shortcut_undo": "Undo",
+  "help.shortcut_redo": "Redo",
+  "help.advanced_use_cases": "Advanced use cases",
+  "help.use_cases": "Use cases",
+  "help.other": "Other",
+  "help.supported_languages": "Many languages supported",
+  "help.active_filter_chips": "Active filter chips",
+  "help.clickable": "Clickable",
+  "help.breadcrumb_clickable": "Clickable breadcrumb",
+  "help.autocomplete": "Autocomplete",
+  "help.drag_drop_tabs": "Drag & drop tabs",
+  "help.persistent_display": "Persistent display in bar",
+  "help.close_tab_x": "✕ button",
+  "help.activation": "Activation",
+  "help.add_remove": "Add/Remove",
+  "help.nodes_edges": "Edges",
+  "help.graph_zoom_pan": "Scroll wheel zoom & pan",
+  "help.graph_fullscreen": "Full screen & PNG export",
+  "help.graph_filter_depth": "Filters & depth",
+  "help.graph_focus": "Focus mode",
+  "help.graph_navigation": "History navigation ← → ↑",
+  "help.graph_sticky": "Sticky panels",
+  "help.graph_preview": "Ctrl+hover",
+  "help.rendering_images": "Image rendering",
+  "help.wikilinks": "Wikilinks",
+  "help.syncthing": "Syncthing conflicts",
+  "help.public_shares": "Public sharing",
+  "help.webhooks": "Webhooks",
+  "help.dashboard": "Dashboard statistics",
+  "help.pdf_export": "PDF export",
+  "help.command_palette": "Command palette",
+  "help.search_dropdown": "Search dropdown",
+  "help.results_counter": "Results counter",
+  "help.sort_options": "Sort options",
+  "help.filter_toggles": "Toggles Aa, wd, .*",
+  "help.mobile": "Floating results bar",
+  "help.theme_sync": "Synced theme",
+  "help.configuration": "Settings",
+  "help.footer": "© 2026 — Made with ☕, 🎧 and a few",
+  "help.nights": "sleepless nights 😅",
+  "help.powered_by": "Powered by Python, FastAPI, vanilla JS, CodeMirror, Mermaid, Lucide Icons and ❤️ for Obsidian.",
 
   "auth.login_title": "Secure access to your vaults",
   "auth.username": "Username",
   "auth.password": "Password",
   "auth.login_button": "Sign in",
-  "auth.remember_me": "Remember me",
+  "auth.remember_me": "Remember me (30 days)",
   "auth.login_error": "Invalid credentials",
   "auth.network_error": "Network error — check your connection",
   "auth.logged_out": "Signed out",
@@ -187,6 +454,8 @@
 
   "palette.search_files": "Search files...",
   "palette.search_commands": "Type a command...",
+  "palette.mode_files": "Files",
+  "palette.mode_commands": "Commands",
 
   "offline.status": "Offline",
   "offline.pending": "{count} pending change(s)",
@@ -236,6 +505,7 @@
   "toast.error_delete": "Delete error",
   "toast.error_load": "Loading error",
   "toast.error_network": "Network error",
+  "toast.error_init": "Initialization error",
   "toast.reindex_started": "Reindexing...",
   "toast.reindex_done": "Reindexing complete",
   "toast.index_reloaded": "Full index reloaded",
@@ -244,6 +514,18 @@
   "toast.config_saved": "Configuration saved",
   "toast.config_client_saved": "Client settings saved",
   "toast.config_reset": "Configuration reset",
+  "toast.ai_no_key": "No keys to save",
+  "toast.ai_keys_saved": "API keys saved",
+  "toast.user_created": "User created",
+  "toast.user_modified": "User modified",
+  "toast.user_deleted": "User deleted",
+  "toast.cannot_delete_self": "Cannot delete your own account",
+  "toast.url_required": "URL required",
+  "toast.share_revoked": "Share revoked",
+  "toast.link_created": "Link created!",
+  "toast.conflict_resolved": "Conflict resolved",
+  "toast.search_saved": "Search saved",
+  "toast.hidden_saved": "✓ Settings saved",
 
   "confirm.logout": "Are you sure you want to sign out?",
   "confirm.delete_file": "Permanently delete this file?",
@@ -267,5 +549,7 @@
   "vault.reindex": "Reindex vault",
 
   "theme.light": "Light",
-  "theme.dark": "Dark"
+  "theme.dark": "Dark",
+  "theme.change": "Change theme",
+  "theme.title": "Theme"
 }