Add Opencode and Ollama modules; update configs

Enable Opencode and Ollama in home modules and import their Nix files.
Disable the deprecated system‑module opencode entries and remove it from
the
core packages list.
Add a new GitHub CLI module and a convenient `upf-gh` alias for flake
updates using a GitHub token.
Update the `stylix` configuration to include Opencode styling.
Refresh several flake.lock entries with newer revisions and hashes.

modules/home/fish/aliases.nix

@@ -9,6 +9,7 @@
     upd = "nh os switch -H ${host} -d always";
     upg = "nh os switch -H ${host} --update  -d always";
     upf = "sudo nix flake update --flake /home/${username}/garandos";
+    upf-gh = "nix flake update --option access-tokens \"github.com=$(gh auth token)\" --flake /home/${username}/garandos";
     upf-undo = "git -C /home/${username}/garandos restore /home/${username}/garandos/flake.lock";
     upd-bt = "nh os boot -H ${host} -d always";
     upd-ts = "nh os test -H ${host} -d always";