v2.4.0: Editor redesign for HA 2026.x, storage isolation, and Dutch

This release ships an editor redesign for Home Assistant 2026.x, isolates per-card storage, and adds Dutch.

✨ New Features

• Dutch language support: Full Dutch (nl) translation added to the card and the visual editor's language selector. Thanks to @JosHarink for the strings.

🎨 Editor (HA 2026.x)

• ha-input migration: Text and number inputs were silently empty on HA 2026.4+ because the ha-form selectors moved from ha-textfield to a new ha-input component. The editor now picks the right tag at render time using lit's static-html, with a runtime fallback for older HA. See the HA frontend 2026.4 blog post.
• ha-select rewrite: HA 2026.x rewrote ha-select to read options from a .options property instead of slotted <mwc-list-item> children. All editor selects now bind their options array directly and emit via ev.detail.value / ev.detail.index.
• Picker force-loading: Entity picker, icon picker, and text inputs are force-loaded via a hidden ha-form so they're defined even when HA hasn't auto-imported them yet.
• Layout cleanup: CSS scoping fixed around .panel-body / .entity-options so editor fields stretch correctly inside their flex containers.
• Language selector is now sorted alphabetically by native name and includes Dutch (Hebrew kept at the end as the only non-Latin label).

🐛 Fixes

• Storage namespace isolation (#94): Two cards on the same dashboard view no longer share localStorage. The namespace fallback chain is now storage_namespace > default_timer_entity > first entity in entities: > per-instance random key, so unconfigured cards each get their own bucket. Existing configs using storage_namespace or default_timer_entity are unaffected.

📖 Docs

• README and CONFIGURATION updated for Dutch.
• New storage_namespace documented in the Storage section, including the multi-card dashboard pattern.