feat(home): add pass-backed keyring module and enable for work VM

- Add modules/home/security/pass-keyring with GPG agent, pass, and
  python keyring backend config for headless credential storage
- Enable pass-keyring for lin-va-mbp-work-vm
- Update bash PATH from ~/.bin to ~/.local/bin

modules/home/security/pass-keyring/default.nix

@@ -0,0 +1,40 @@
+{ config
+, lib
+, namespace
+, pkgs
+, ...
+}:
+let
+  inherit (lib) mkIf mkEnableOption;
+
+  cfg = config.${namespace}.security.pass-keyring;
+in
+{
+  options.${namespace}.security.pass-keyring = {
+    enable = mkEnableOption "Enable pass-backed keyring";
+  };
+
+  config = mkIf cfg.enable {
+    home.packages = [ pkgs.pass ];
+
+    # GPG + Pass Keyring - Provides credential storage for CLI
+    # tools (e.g. python keyring) via pass (GPG-backed). The
+    # keyringrc.cfg forces keyring to use the pass backend instead
+    # of SecretService (which requires a working D-Bus provider).
+    programs.gpg.enable = true;
+    services.gpg-agent = {
+      enable = true;
+      enableBashIntegration = true;
+      pinentry.package = pkgs.pinentry-curses;
+      defaultCacheTtl = 86400; # 24 hours
+      maxCacheTtl = 604800; # 7 days
+    };
+
+    # Keyring Backend Config - Forces keyring to use the pass
+    # backend instead of SecretService (broken on headless Linux).
+    xdg.configFile."python_keyring/keyringrc.cfg".text = ''
+      [backend]
+      default-keyring=keyring_pass.PasswordStoreBackend
+    '';
+  };
+}