fix: remove tauri-plugin-log to avoid logger conflict

`tracing_subscriber::fmt().try_init()` installs a global log
implementation via the tracing-log shim. tauri-plugin-log then
calls `log::set_logger()` which panics with "attempted to set a
logger after the logging system was already initialized".

The plugin was never wired in JS code (no @tauri-apps/plugin-log
import) — backend logging via tracing is sufficient. Drop:
  - tauri-plugin-log dep + plugin registration
  - log:default capability permission
  - @tauri-apps/plugin-log JS dep

Verified: cargo check is clean, app starts past the panic.

src-tauri/Cargo.toml

@@ -17,7 +17,6 @@ tauri-build = { version = "2", features = [] }
 tauri = { version = "2", features = [] }
 tauri-plugin-shell = "2"
 tauri-plugin-store = "2"
-tauri-plugin-log = "2"
 tauri-plugin-dialog = "2"
 serde = { version = "1", features = ["derive"] }
 serde_json = "1"