* chore(deps): bump rusqlite to 0.40 workspace-wide
Align root src-tauri and workspace crates on rusqlite 0.40 so libsqlite3-sys
resolves to a single version (fixes Dependabot #913 links conflict).
* chore(nix): refresh flake.lock for rustc 1.95 dev shell
libsqlite3-sys 0.38 (rusqlite 0.40) needs cfg_select; nixpkgs pin was on
rustc 1.94. Bump workspace MSRV to 1.95 to match.