fix: convert antfarm from broken submodule to regular directory

Fixes Gitea 500 error caused by invalid submodule reference.
Converted antfarm from pseudo-submodule (missing .gitmodules) to
regular directory with all source files.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

antfarm/src/installer/symlink.ts

@@ -0,0 +1,73 @@
+import { existsSync, mkdirSync, symlinkSync, unlinkSync, readlinkSync } from "fs";
+import { join } from "path";
+import { fileURLToPath } from "url";
+
+const BINARY_NAME = "antfarm";
+
+/**
+ * Ensure `antfarm` is available on PATH by symlinking into ~/.local/bin.
+ * Safe to call repeatedly — skips if already correct, updates if stale.
+ */
+export function ensureCliSymlink(): void {
+  const home = process.env.HOME;
+  if (!home) return;
+
+  const localBin = join(home, ".local", "bin");
+  const linkPath = join(localBin, BINARY_NAME);
+
+  // Resolve the actual CLI entry point (dist/cli/cli.js)
+  const cliEntry = join(
+    fileURLToPath(import.meta.url),
+    "..",
+    "..",
+    "cli",
+    "cli.js",
+  );
+
+  try {
+    mkdirSync(localBin, { recursive: true });
+  } catch {
+    // already exists
+  }
+
+  // Check existing symlink
+  if (existsSync(linkPath)) {
+    try {
+      const current = readlinkSync(linkPath);
+      if (current === cliEntry) return; // already correct
+    } catch {
+      // not a symlink or unreadable — replace it
+    }
+    try {
+      unlinkSync(linkPath);
+    } catch {
+      console.warn(`  ⚠ Could not update symlink at ${linkPath}`);
+      return;
+    }
+  }
+
+  try {
+    symlinkSync(cliEntry, linkPath);
+    console.log(`  ✓ Symlinked ${BINARY_NAME} → ${localBin}`);
+  } catch (err) {
+    console.warn(`  ⚠ Could not create symlink: ${err instanceof Error ? err.message : String(err)}`);
+  }
+}
+
+/**
+ * Remove the CLI symlink (used during uninstall).
+ */
+export function removeCliSymlink(): void {
+  const home = process.env.HOME;
+  if (!home) return;
+
+  const linkPath = join(home, ".local", "bin", BINARY_NAME);
+  if (existsSync(linkPath)) {
+    try {
+      unlinkSync(linkPath);
+      console.log(`  ✓ Removed symlink ${linkPath}`);
+    } catch {
+      console.warn(`  ⚠ Could not remove symlink at ${linkPath}`);
+    }
+  }
+}