feat(mobile): ruban d'edition style Obsidian + correctifs mobile (#83, BUG-017 a BUG-020)

- #83: ruban horizontal defilable ancre au-dessus du clavier, commandes
  etendues (titres, barre, surligne, code bloc, citation, listes, cases,
  wikilinks, tags, pieces jointes, undo/redo, colle, police) et
  personnalisation persistee via l'icone engrenage
- BUG-017: cartes du tableau de bord compressibles (min-width:0)
- BUG-018: en-tete editeur mobile compact, boutons Annuler/Sauvegarder
  accessibles, barre IA plus tactile
- BUG-019: ancrage du ruban via visualViewport (--kb-offset)
- BUG-020: suppression de la double barre de defilement

Tests: mobile-editor 35/35, ai 50/50, 9 suites JSDOM, validate-imports,
pytest 961 passed / 6 skipped, ruff + mypy 0.

frontend/locales/en.json

@@ -1143,8 +1143,8 @@
   "help.mobile_editor_reading": ": full screen without header or sidebars; swipe horizontally to go to the next or previous file.",
   "help.mobile_editor_reading_label": "Reading mode",
   "help.mobile_editor_title": "📱 Mobile editing",
-  "help.mobile_editor_toolbar": ": bold, italic, code, bullet list and link. The A−/A+ buttons adjust the font size.",
-  "help.mobile_editor_toolbar_label": "Floating toolbar",
+  "help.mobile_editor_toolbar": ": horizontally scrollable ribbon (headings, bold, italic, strikethrough, highlight, code, quote, lists, checkboxes, links, tags, attachments). The ⚙ icon lets you add, remove or reorder commands; A−/A+ adjust the font size.",
+  "help.mobile_editor_toolbar_label": "Editing ribbon",
   "help.mobile_editor_zoom": ": pinch with two fingers to zoom, drag the handle to resize the editing area.",
   "help.mobile_editor_zoom_label": "Zoom & height",
   "help.modal_title": "ObsiGate User Guide",
@@ -1307,10 +1307,40 @@
   "mermaid.zoom_in": "Zoom in",
   "mermaid.zoom_out": "Zoom out",
   "mobile.all_vaults": "📂 All vaults",
+  "mobile_editor.add_command": "Add a command",
   "mobile_editor.backlinks": "Backlinks",
   "mobile_editor.bold": "Bold",
   "mobile_editor.close": "Close",
+  "mobile_editor.cmd_attachment": "Attachment",
+  "mobile_editor.cmd_bold": "Bold",
+  "mobile_editor.cmd_bullet": "Bullet list",
+  "mobile_editor.cmd_checkbox": "Checkbox",
+  "mobile_editor.cmd_code": "Inline code",
+  "mobile_editor.cmd_codeblock": "Code block",
+  "mobile_editor.cmd_dedent": "Outdent",
+  "mobile_editor.cmd_files": "Template / files",
+  "mobile_editor.cmd_h1": "Heading 1",
+  "mobile_editor.cmd_h2": "Heading 2",
+  "mobile_editor.cmd_h3": "Heading 3",
+  "mobile_editor.cmd_h4": "Heading 4",
+  "mobile_editor.cmd_h5": "Heading 5",
+  "mobile_editor.cmd_h6": "Heading 6",
+  "mobile_editor.cmd_highlight": "Highlight",
+  "mobile_editor.cmd_indent": "Indent",
+  "mobile_editor.cmd_italic": "Italic",
+  "mobile_editor.cmd_link": "External link",
+  "mobile_editor.cmd_ordered": "Numbered list",
+  "mobile_editor.cmd_quote": "Quote",
+  "mobile_editor.cmd_redo": "Redo",
+  "mobile_editor.cmd_strike": "Strikethrough",
+  "mobile_editor.cmd_tag": "Tag",
+  "mobile_editor.cmd_undo": "Undo",
+  "mobile_editor.cmd_wikilink": "Internal link",
   "mobile_editor.code": "Code",
+  "mobile_editor.customize": "Customize toolbar",
+  "mobile_editor.customize_reset": "Reset",
+  "mobile_editor.customize_title": "Customize toolbar",
+  "mobile_editor.done": "Done",
   "mobile_editor.error": "Loading error",
   "mobile_editor.font_larger": "Increase font size",
   "mobile_editor.font_smaller": "Decrease font size",
@@ -1318,6 +1348,8 @@
   "mobile_editor.link": "Link",
   "mobile_editor.list": "Bullet list",
   "mobile_editor.loading": "Loading…",
+  "mobile_editor.move_down": "Move down",
+  "mobile_editor.move_up": "Move up",
   "mobile_editor.no_backlinks": "No backlinks",
   "mobile_editor.no_headings": "No headings in this document",
   "mobile_editor.no_next": "Last file in folder",
@@ -1326,6 +1358,7 @@
   "mobile_editor.paste_hint": "Long-press the field then choose “Paste” (clipboard access denied).",
   "mobile_editor.reading_enter": "Reading mode",
   "mobile_editor.reading_exit": "Exit reading mode",
+  "mobile_editor.remove_command": "Remove",
   "mobile_editor.resize": "Adjust editor height",
   "mobile_editor.toc": "Table of contents",
   "mobile_editor.toolbar": "Mobile editing toolbar",