feat: add ability to configure the agent (also theme switcher) (#3)

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### Dependencies

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### Tests

- [ ] My contribution adds new code, and I have added tests to cover it.
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Reviewed-on: #3
Co-authored-by: Naomi Carrigan <commits@nhcarrigan.com>
Co-committed-by: Naomi Carrigan <commits@nhcarrigan.com>

pnpm-lock.yaml

@@ -20,6 +20,9 @@ importers:
       '@tauri-apps/plugin-shell':
         specifier: ^2.3.4
         version: 2.3.4
+      '@tauri-apps/plugin-store':
+        specifier: ^2
+        version: 2.4.2
     devDependencies:
       '@eslint/js':
         specifier: ^9.39.2
@@ -729,6 +732,9 @@ packages:
   '@tauri-apps/plugin-shell@2.3.4':
     resolution: {integrity: sha512-ktsRWf8wHLD17aZEyqE8c5x98eNAuTizR1FSX475zQ4TxaiJnhwksLygQz+AGwckJL5bfEP13nWrlTNQJUpKpA==}
 
+  '@tauri-apps/plugin-store@2.4.2':
+    resolution: {integrity: sha512-0ClHS50Oq9HEvLPhNzTNFxbWVOqoAp3dRvtewQBeqfIQ0z5m3JRnOISIn2ZVPCrQC0MyGyhTS9DWhHjpigQE7A==}
+
   '@testing-library/dom@10.4.1':
     resolution: {integrity: sha512-o4PXJQidqJl82ckFaXUeoAW+XysPLauYI43Abki5hABd853iMhitooc6znOnczgbTYmEP6U6/y1ZyKAIsvMKGg==}
     engines: {node: '>=18'}
@@ -2265,6 +2271,10 @@ snapshots:
     dependencies:
       '@tauri-apps/api': 2.9.1
 
+  '@tauri-apps/plugin-store@2.4.2':
+    dependencies:
+      '@tauri-apps/api': 2.9.1
+
   '@testing-library/dom@10.4.1':
     dependencies:
       '@babel/code-frame': 7.28.6