fix: remove unused tauri-plugin-updater + SQLCipher 16KB page size

Two startup crashes on first-party Tauri plugin init:
- tauri-plugin-updater registered with no plugins.updater config → removed
- tauri-plugin-cli was already removed in a prior commit

SQLCipher page size fix:
- cipher_page_size 4096 → 16384
- 4KB SQLCipher pages cause malloc() failures on Linux kernels with
  16KB page size (Asahi Linux aarch64+16k, Apple Silicon)
- 16384 is a valid page size that works on both 4KB and 16KB page kernels
- New installs get a 16KB-page database; existing 4KB-page DBs must
  be deleted for the new page size to take effect

Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>

src-tauri/Cargo.toml

@@ -17,7 +17,6 @@ tauri-plugin-dialog = "2"
 tauri-plugin-fs = "2"
 tauri-plugin-shell = "2"
 tauri-plugin-http = "2"
-tauri-plugin-updater = "2"
 rusqlite = { version = "0.31", features = ["bundled-sqlcipher-vendored-openssl"] }
 serde = { version = "1", features = ["derive"] }
 serde_json = "1"

src-tauri/src/db/connection.rs

@@ -9,7 +9,7 @@ pub fn open_encrypted_db(path: &Path, key: &str) -> anyhow::Result<Connection> {
     conn.execute_batch("SELECT count(*) FROM sqlite_master;")?;
     // Set SQLCipher settings for AES-256
     conn.execute_batch(
-        "PRAGMA cipher_page_size = 4096; \
+        "PRAGMA cipher_page_size = 16384; \
          PRAGMA kdf_iter = 256000; \
          PRAGMA cipher_hmac_algorithm = HMAC_SHA512; \
          PRAGMA cipher_kdf_algorithm = PBKDF2_HMAC_SHA512;",

src-tauri/src/lib.rs

@@ -51,7 +51,6 @@ pub fn run() {
         .plugin(tauri_plugin_fs::init())
         .plugin(tauri_plugin_shell::init())
         .plugin(tauri_plugin_http::init())
-        .plugin(tauri_plugin_updater::Builder::new().build())
         .manage(app_state)
         .invoke_handler(tauri::generate_handler![
             // DB / Issue CRUD