fix(showcase/ms-agent-python): declarative-gen-ui A2UI surface mount

Two stacked causes kept the A2UI surface from binding to the registered
catalog despite the SSE payload reaching the browser correctly:

1. `tools/generate_a2ui.py::build_a2ui_operations_from_tool_call` emitted
   ops in a deprecated FLAT shape (`{"type": "create_surface",
   "surfaceId": ...}`). The `@ag-ui/a2ui-middleware` extracts surfaceId
   via `op.createSurface?.surfaceId ?? op.updateComponents?.surfaceId
   ?? ...` — the v0.9 NESTED shape that `copilotkit.a2ui.create_surface`
   produces. With the flat shape every op was grouped under a "default"
   surface key and the renderer never bound to the catalog. Rewrote the
   builder to mirror the LGP nested shape.

2. `@copilotkit/*` was pinned to `next` (resolved to `1.55.2-next.1`)
   while LGP pins exactly `1.57.2`. The published `@copilotkit/web-
   inspector@1.57.2` carries a `workspace:*` dep to `@copilotkit/core`
   that npm rejects with EUNSUPPORTEDPROTOCOL — added the same
   `overrides` / `pnpm.overrides` block LGP uses to short-circuit the
   resolution.

Also synced `tests/e2e/declarative-gen-ui.spec.ts` from LGP to un-skip
the KPI dashboard and Status report tests (LGP resolved the W8-7
Railway slowness skips by splitting the fixtures; MAF spec hadn't
caught up). 6/6 declarative-gen-ui tests now pass.

Author: AlemTuzlak