Expose every Bulma variant as a choosable option, not just a curated few

Adds a shared bulma_variants.py (color/size option lists) and expands BULMA_*_CONTROLS in bulma_controls.py to cover each component's full modifier set: Bouton (colour incl. white/light/dark/black/text, light-shade toggle, size, rounded, outlined, inverted, static, loading, fullwidth), Titre (Bulma size is-1..is-6 independent of heading level, is-spaced), Jauge (size), Tableau (bordered/fullwidth/striped/hoverable/narrow, now toggleable instead of hardcoded), Onglets (alignment, boxed/toggle/toggle-rounded style, size, fullwidth), and every form field — champ_texte/email/mot_de_passe, zone_texte, liste_deroulante (colour, size, rounded, static).

render_select.py/render_onglets.py/render_jauge.py now redirect the merged "class" from _visible_attrs to the actual Bulma sub-element (the .select wrapper, the .tabs div, the <progress> tag) instead of the outer positioning wrapper, since that's what needs to carry the modifier classes.

Also fixed a real latent bug found while wiring this up: a checkbox control with default=True (e.g. Tableau's "Première ligne = en-tête") was never actually applied on a freshly created element — default_style_and_attributes unconditionally skipped ALL checkbox types at creation, so the panel showed it checked while the element itself had nothing set. Now a checkbox's default=True is frozen at creation like any other meaningful default; default=False (the common case) is unaffected.

Verified end to end: every widget's variant controls save and render the right class tokens (spot-checked titre/tableau/onglets/champ_texte/liste_deroulante/jauge), full suite green (89 passed).

screens/rendering/render_onglets.py

@@ -21,6 +21,10 @@ def _render_onglets(el, meta, slug, children_map=None, ctx=None, parent_flex_dir
 
     tabs = (children_map or {}).get(el["id"], [])
     attrs = _visible_attrs(el, meta, ctx)
+    # Les variantes Bulma (alignement/style/taille... voir BULMA_TABS_CONTROLS)
+    # calculées par _visible_attrs atterrissent dans "class" — c'est le
+    # <div class="tabs"> qui doit les porter, pas ce wrapper de positionnement.
+    tabs_extra_classes = attrs.pop("class", "")
     style = _style_string(el, " display:flex; flex-direction:column;", parent_flex_direction)
     group_id = _auto_id(el)
 
@@ -53,9 +57,10 @@ def _render_onglets(el, meta, slug, children_map=None, ctx=None, parent_flex_dir
             f'{tab_html}</div>'
         )
 
+    tabs_class = html_lib.escape(("tabs " + tabs_extra_classes).strip())
     return (
         f'<div {_attr_string(attrs, style)}>'
-        f'<div class="tabs"><ul>{"".join(bar_items)}</ul></div>'
+        f'<div class="{tabs_class}"><ul>{"".join(bar_items)}</ul></div>'
         f'<div class="forgeTabPanels" style="flex:1 1 auto; min-height:0;">{"".join(panels)}</div>'
         f"</div>"
     )