feat: scaffold CLI and minimal issue list (task 0001)

Tracer bullet for gitea-axi: runnable npm package on axi-sdk-js with
gitea-js as the sole HTTP layer, ESM on Node 20+.

- issue list with --state/--limit, default fields, count line from
  X-Total-Count, type=issues guard, explicit empty state, and next-step
  suggestions
- repo context detection from the git origin remote (SSH/scp/HTTPS),
  tea credential discovery with the three-way login-matching split, and
  -R/--repo and --login overrides (flag > env > auto)
- token retrieval via tea login helper get: tea's login list JSON
  carries no token (ADR 0001 amended)
- full AxiError classification table with path-based 404 split, TOON
  errors on stdout, exit codes 0/1/2
- test mode (GITEA_AXI_API_URL/TOKEN/REPO) suppressing subprocesses,
  fixture server, and vitest suites driving the CLI seam (50 tests)

src/git.ts

@@ -0,0 +1,55 @@
+import type { CliDeps } from "./deps.js";
+import { runSubprocess } from "./subprocess.js";
+
+export interface RemoteRepo {
+  host: string;
+  owner: string;
+  name: string;
+}
+
+function parseRepoPath(rawPath: string): { owner: string; name: string } | null {
+  const path = rawPath.replace(/^\/+/, "").replace(/\/+$/, "").replace(/\.git$/, "");
+  const segments = path.split("/");
+  if (segments.length !== 2 || !segments[0] || !segments[1]) {
+    return null;
+  }
+  return { owner: segments[0], name: segments[1] };
+}
+
+export function parseRemoteUrl(url: string): RemoteRepo | null {
+  const trimmed = url.trim();
+  if (/^(https?|ssh):\/\//.test(trimmed)) {
+    let parsed: URL;
+    try {
+      parsed = new URL(trimmed);
+    } catch {
+      return null;
+    }
+    const repo = parseRepoPath(parsed.pathname);
+    if (!repo || !parsed.hostname) {
+      return null;
+    }
+    return { host: parsed.hostname, ...repo };
+  }
+  // scp-like SSH form: [user@]host:owner/name[.git]
+  const scp = /^(?:[^@/\s]+@)?([^:/\s]+):(.+)$/.exec(trimmed);
+  if (scp) {
+    const repo = parseRepoPath(scp[2]!);
+    if (!repo) {
+      return null;
+    }
+    return { host: scp[1]!, ...repo };
+  }
+  return null;
+}
+
+export async function detectRemote(deps: CliDeps): Promise<RemoteRepo | null> {
+  const result = await runSubprocess("git", ["remote", "get-url", "origin"], {
+    cwd: deps.cwd,
+    env: deps.env,
+  });
+  if (result.enoent || result.code !== 0) {
+    return null;
+  }
+  return parseRemoteUrl(result.stdout);
+}