feat(gitea-axi): install the CLI and wire its agent context

Add gitea-axi as a flake input and a new modules.gitea-axi module that
installs the CLI through its home-manager module. That module also declares
the Claude Code context — the Agent Skill and the SessionStart dashboard hook
— when claude-code is enabled on the host, so neogaia gets both while a host
without the harness would get the CLI alone.

Drop the hand-written SessionStart hook from the claude-code module, which
named a gitea-axi binary nothing installed; the gitea-axi module owns it now.
Remove the vendored skill fork, which had drifted from upstream and would
collide with the copy the module writes.

modules/claude-code/claude-code.nix

@@ -77,18 +77,6 @@ in
                 ];
               }
             ];
-            SessionStart = [
-              {
-                matcher = "";
-                hooks = [
-                  {
-                    type = "command";
-                    command = "gitea-axi";
-                    timeout = 10;
-                  }
-                ];
-              }
-            ];
           };
         };
       };

modules/claude-code/skills/gitea-axi/SKILL.md

@@ -1,48 +0,0 @@
----
-name: gitea-axi
-description: Use when working with a Gitea repository's issues, pull requests, labels, reviews, comments, or milestones — listing, viewing, creating, editing, commenting, reviewing, or merging on a Gitea host such as git.alexion.dev. Prefer this over the `tea` CLI, raw Gitea API calls, or improvised `git` commands for issue/PR/label work.
----
-
-# gitea-axi
-
-`gitea-axi` is an agent-ergonomic CLI for a Gitea repository's issues and pull requests.
-Its output is compact TOON built for another program to read, and its errors are structured with actionable suggestions.
-
-## When to use it
-
-Reach for `gitea-axi` whenever a task touches a Gitea repository's issues, pull requests, labels, or reviews.
-
-- **Over `tea`:** `gitea-axi` returns structured output and typed errors instead of human-formatted tables, and it defaults the repository and login from the local checkout.
-- **Over raw Gitea API calls:** it handles auth, pagination, name-to-ID resolution, and review-decision aggregation for you, so you do not hand-roll HTTP.
-- **Over improvised `git`:** for anything about issues or pull requests as entities (state, reviews, labels, comments) rather than local commits and branches.
-
-## Targeting and authentication
-
-Every command resolves two things: which repository to act on, and which credentials to authenticate with.
-Get both right on the first call — they are the usual reason a command fails and has to be retried.
-
-- **Repository.** Inside a Gitea checkout it is taken from the `origin` remote automatically.
-  Outside a checkout you must name it: pass `-R OWNER/NAME` on every command (or set `GITEA_AXI_REPO=OWNER/NAME` once for the session).
-- **Credentials.** When the environment is pre-configured — `GITEA_AXI_TOKEN` together with `GITEA_AXI_API_URL` — authentication is automatic and you need nothing more.
-  Otherwise credentials come from a `tea` login: pass `--login <name>` (or set `GITEA_AXI_LOGIN=<name>`) unless the checkout's remote already selects one.
-
-So outside a checkout with the token in the environment, `gitea-axi <command> -R OWNER/NAME …` is all you need; do not go hunting for a config file or a login profile.
-
-## Command groups
-
-- `issue` — list, view, create, comment on, edit, close/reopen, pin, and link issues.
-- `pr` — create, view, comment on, edit, review, merge, check out, diff, and inspect the checks of pull requests.
-- `label` — list, create, edit, and delete labels.
-- `search` — full-text search; it takes a subcommand, so search issues with `search issues "<query>"` and pull requests with `search prs "<query>"` (a bare `search "<query>"` is not valid).
-- `setup` — install this skill (`setup`) and, opt-in, the SessionStart dashboard hook (`setup hooks`).
-
-To read one issue's fields, reach straight for `issue view <number>`: it shows labels and state by default, and takes `--fields assignees,milestone,…` for the rest.
-You rarely need `issue list` to answer a question about a single issue.
-
-## Discovery
-
-This skill is a pointer, not a command reference — the CLI is the single source of truth for its own interface.
-
-- Run `gitea-axi` with no arguments for the repository dashboard (open issues and pull requests).
-  Add `--full` for the open-PR table and issue counts by label.
-- Run `gitea-axi <command> --help` (or `gitea-axi <group> <command> --help`) for the exact flags of any command.

modules/gitea-axi.nix

@@ -0,0 +1,22 @@
+{
+  config,
+  lib,
+  inputs,
+  ...
+}:
+# gitea-axi for the primary user, installed through its own home-manager module.
+# That module also declares the Claude Code context when that harness is
+# enabled on the host; enabling this alone installs the CLI and nothing else.
+let
+  cfg = config.modules.gitea-axi;
+  user = config.user.name;
+in
+{
+  options.modules.gitea-axi.enable =
+    lib.mkEnableOption "gitea-axi, an agent-ergonomic CLI for Gitea issues and pull requests";
+
+  config = lib.mkIf cfg.enable {
+    home-manager.sharedModules = [ inputs.gitea-axi.homeModules.default ];
+    home-manager.users.${user}.programs.gitea-axi.enable = true;
+  };
+}