Fix bit(1) import coercion and subpath login redirect

The WJ import loader coerced MySQL bit(1) columns with bool(), which is
always true for the bytes pymysql returns; applications.isinstallable
and notifications.isshopfloor imported as 1 for every row. Route both
through the existing _truthy_bit helper. The loader also no longer
requires the employee source database: without it, notifications keep
the bare SSO and the verify stage skips the employee count.

Under a subpath mount, the session-expiry interceptor stored the
browser path (which includes the mount base) as the login redirect,
and the router applied its base again after login. Add stripBase()
and store base-free router paths; the login page also strips a stale
base from old bookmarked redirects.

Also point the external-plugin CI helper at the repo's GitHub URL.

frontend/src/utils/basePath.js

@@ -11,3 +11,15 @@ export function withBase(path) {
   if (/^([a-z]+:)?\/\//i.test(path) || path.startsWith('data:')) return path
   return BASE_URL + String(path).replace(/^\//, '')
 }
+
+// Inverse of withBase: turn a browser pathname (which includes the mount
+// base, e.g. '/ops/computers') into a router path ('/computers'). Router
+// navigation already applies the base; feeding it an un-stripped pathname
+// double-prefixes ('/ops/ops/...').
+export function stripBase(path) {
+  if (!path) return path
+  if (BASE_URL !== '/' && path.startsWith(BASE_URL)) {
+    return '/' + path.slice(BASE_URL.length)
+  }
+  return path
+}