Add per-parameter "visible in symbol" flag for KiCad EDA export (#1444)

* Add per-parameter "visible in symbol" flag for KiCad EDA export

Introduce a nullable tri-state eda_symbol_visibility on part parameters
that drives the KiCad field's "visible" flag in the EDA HTTP-library API
response. This is independent of the existing eda_visibility, which only
controls whether the parameter is exported as a field at all.

When the per-parameter flag is null, the new system default
KiCadEDASettings::defaultParameterSymbolVisibility applies. Both default
such that exported parameter fields keep their previous behavior
("visible": "False"), so the change is backward compatible.

- Entity: eda_symbol_visibility column + accessors, with matching
  serialization groups and a multi-platform migration
- Form: second TriStateCheckboxType, shown for part parameters only
- KiCadHelper: resolve the flag (explicit, else system default) and pass
  it to createField()
- Settings: defaultParameterSymbolVisibility (default false)
- Templates: new eye-icon column in the specifications table
- Translations (en) + tests

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

* Fixed message ids

---------

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Co-authored-by: Jan Böhmer <mail@jan-boehmer.de>

src/Entity/Parameters/AbstractParameter.php

@@ -179,6 +179,14 @@ abstract class AbstractParameter extends AbstractNamedDBElement implements Uniqu
     #[ORM\Column(type: Types::BOOLEAN, nullable: true, options: ['default' => null])]
     protected ?bool $eda_visibility = null;
 
+    /**
+     * @var bool|null Whether the exported EDA field should be visible in the schematic symbol
+     *                (sets the KiCad field's "visible" flag). Null means use system default.
+     */
+    #[Groups(['full', 'parameter:read', 'parameter:write', 'import'])]
+    #[ORM\Column(type: Types::BOOLEAN, nullable: true, options: ['default' => null])]
+    protected ?bool $eda_symbol_visibility = null;
+
     /**
      * Mapping is done in subclasses.
      *
@@ -493,6 +501,21 @@ abstract class AbstractParameter extends AbstractNamedDBElement implements Uniqu
         return $this;
     }
 
+    public function isEdaSymbolVisibility(): ?bool
+    {
+        return $this->eda_symbol_visibility;
+    }
+
+    /**
+     * @return $this
+     */
+    public function setEdaSymbolVisibility(?bool $eda_symbol_visibility): self
+    {
+        $this->eda_symbol_visibility = $eda_symbol_visibility;
+
+        return $this;
+    }
+
     public function getComparableFields(): array
     {
         return ['name' => $this->name, 'group' => $this->group, 'element' => $this->element?->getId()];