Revert PR #2 — plugin moved to single-segment URL, fix no longer needed

[nothing-stops-this-train]

Revert of #2.

#2 patched Nuxt's getLocation quirk so that plugin routes one or more segments deep below the admin base (e.g. `/admin/plugins/liquidityhelper`) would resolve on a fresh load. That worked, but it's a workaround in the bitcart-admin tree for what is really a plugin-side decision.

The liquidityhelper plugin route is now a single segment (`/admin/liquidityhelper` — see BareBits/bitcart_liquidity@), which sidesteps the quirk entirely. Single-segment URLs already work on upstream router.js — that's how every built-in admin page (`/admin/stores`, `/admin/invoices`, `/admin/plugins`) loads. So we no longer need the trailing-slash normalization, and reverting keeps this fork minimally diverged from upstream bitcart-admin.

Test plan

• Rebuild admin image from this branch + redeploy liquidityhelper plugin with its new `/liquidityhelper` route.
• Hard-reload `/admin/liquidityhelper` — plugin page renders on first paint.
• Hard-reload `/admin/stores` — still works (sanity-check; nothing else regressed).
• Hard-reload `/admin/plugins/liquidityhelper` — clean 404 (route no longer exists, as expected).

[nothing-stops-this-train]

Closing — tested on the regtest rig and the hypothesis didn't hold.

Setup: pointed the VPS at this branch (BITCART_ADMIN_REPO_BRANCH=revert-router-base-trailing-slash), wiped the local clone, ran the plugin deploy with --rebuild. Deployed the companion plugin route change (/plugins/liquidityhelper → /liquidityhelper, single segment). Confirmed the running container's /src/router.js had no trailing-slash normalization and the compiled bundle had the new single-segment route.

Result: 0/6 fresh-context loads of /admin/liquidityhelper rendered the dashboard. All six attempts got the SPA 404 page (title="404 Not Found - bitcart-admin"), even though SSR returned HTTP 200. Restored the fix → 6/6 worked.

So a single-segment URL doesn't sidestep the bug for vuems-registered plugin routes. The recovery that lets /admin/stores survive a corrupted getLocation slice only applies to Nuxt-auto-routed pages — vuems-extended routes added in router.js don't get it. The only ways to actually drop the patch would be to register the plugin page through Nuxt's auto-routing (would require restructuring how bitcart loads UI plugins) or fix it upstream.

Keeping the patch on lnd-integration.