fix: register installed skills in boost.json during add-skill

When `boost:add-skill` downloads a community skill, it calls
`boost:update` to sync skills to agent directories. However,
`boost:update` checks `Config::hasSkills()` which reads the
`"skills"` key from `boost.json`. If the user never ran
`boost:install --skills`, this key doesn't exist, so the sync
is silently skipped — the skill sits in `.ai/skills/` but never
reaches `.claude/skills/`, `.cursor/skills/`, etc.

Fix: register the installed skill names in `boost.json`'s
`"skills"` array before calling `boost:update`, ensuring the
subsequent sync always runs.

Fixes #620

Author: meirdick

src/Console/AddSkillCommand.php

@@ -12,6 +12,7 @@
 use InvalidArgumentException;
 use Laravel\Boost\Concerns\DisplayHelper;
 use Laravel\Boost\Skills\Remote\GitHubRepository;
+use Laravel\Boost\Support\Config;
 use Laravel\Boost\Skills\Remote\GitHubSkillProvider;
 use Laravel\Boost\Skills\Remote\RemoteSkill;
 use Laravel\Prompts\Terminal;
@@ -167,6 +168,7 @@ protected function installSkills(): int
 
             grid($results['installedNames']);
 
+            $this->registerInstalledSkills($results['installedNames']);
             $this->runBoostUpdate();
             $this->showOutro();
         }
@@ -273,6 +275,23 @@ protected function addSkills(Collection $skills, string $absoluteSkillsPath, boo
         return $results;
     }
 
+    /**
+     * Register newly installed skill names in boost.json so that
+     * boost:update knows skills are enabled and syncs them to
+     * agent-specific directories (.claude/skills/, .cursor/skills/, etc.).
+     *
+     * @param  array<int, string>  $installedNames
+     */
+    protected function registerInstalledSkills(array $installedNames): void
+    {
+        $config = app(Config::class);
+
+        $existing = $config->getSkills();
+        $merged = array_values(array_unique(array_merge($existing, $installedNames)));
+
+        $config->setSkills($merged);
+    }
+
     protected function runBoostUpdate(): void
     {
         $this->callSilently(UpdateCommand::class);