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_select.py

@@ -15,6 +15,11 @@ def _render_select(el, meta, slug=None, children_map=None, ctx=None, parent_flex
     # l'élément (comme tous les autres widgets), le <select> reste à
     # l'intérieur avec ses propres attributs de formulaire (name, required).
     outer_attrs = _visible_attrs(el, meta, ctx)
+    # Les variantes Bulma (couleur/taille/arrondi... voir BULMA_FIELD_CONTROLS)
+    # calculées par _visible_attrs atterrissent normalement dans "class" —
+    # ici c'est le <div class="select"> qui doit les porter, pas le <select>
+    # ni le wrapper de positionnement, donc on les redirige à la main.
+    bulma_classes = outer_attrs.get("class", "")
     select_attrs = {k: v for k, v in outer_attrs.items() if k not in ("id", "class", "data-element-id", "data-anim-target")}
     wrapper_attrs = {k: v for k, v in outer_attrs.items() if k in ("id", "data-element-id", "data-anim-target")}
     style = _style_string(el, " display:flex;", parent_flex_direction)
@@ -22,4 +27,5 @@ def _render_select(el, meta, slug=None, children_map=None, ctx=None, parent_flex
     options = [o.strip() for o in content.split("\n") if o.strip()]
     opts_html = "".join(f'<option value="{html_lib.escape(o)}">{html_lib.escape(o)}</option>' for o in options)
     select_html = f'<select {_attr_string(select_attrs, "")}>{opts_html}</select>'
-    return f'<div {_attr_string(wrapper_attrs, style)}><div class="select is-fullwidth">{select_html}</div></div>'
+    select_wrap_class = html_lib.escape(("select is-fullwidth " + bulma_classes).strip())
+    return f'<div {_attr_string(wrapper_attrs, style)}><div class="{select_wrap_class}">{select_html}</div></div>'