Migrate web UI to `/v1/mcp-servers` and `/v1/virtual-servers`

[marekdano]

Related: IBM/mcp-context-forge#4956, IBM/mcp-context-forge#6257

Motivation: mcp-context-forge now serves /v1/mcp-servers (alias of /gateways) and /v1/virtual-servers (alias of /servers) with identical behavior - added in IBM/mcp-context-forge#4956 and shipped via IBM/mcp-context-forge#6257. Legacy paths stay supported server-side indefinitely, but the UI should cut over to the product-language paths.

Scope — hand-written call sites to repoint (the app uses hand-written fetch wrappers for these resources, not orval-generated functions, so this is a string-literal swap, not a codegen regen):

MCP Servers → /gateways to /v1/mcp-servers

• src/api/servers.ts (list, get, update, delete, test — 4+ literal paths)
• src/hooks/useMCPServerForm.ts (create/update/delete gateway)
• src/hooks/useMcpServers.ts
• src/hooks/useMiniCardStatuses.ts
• src/components/dashboard/McpHealthCard.tsx
• src/pages/Servers.tsx (placeholder cache key "/gateways/_placeholder_")

Virtual Servers → /servers to /v1/virtual-servers

• src/api/virtualServers.ts (create, delete, set-state, update)

No BFF changes needed: server/src/routes/proxy/catch-all.ts is a generic /api/* → upstream passthrough (1:1 path forwarding), so the new v1 paths work through the proxy with zero server-side code changes. SSE routes (server/src/routes/sse/routes.ts) don't touch gateways/servers paths at all.

Tests to update:

• Unit: src/api/servers.test.ts, src/api/virtualServers.test.ts, src/pages/Gateways.test.tsx, src/pages/Servers.test.tsx,
  src/hooks/useMiniCardStatuses.test.tsx, src/components/gateways/utils.test.ts
• MSW mocks: src/test/mocks/handlers.ts
• E2E: e2e/servers.spec.ts, e2e/virtual-servers.spec.ts, e2e/utils/paths.ts

Acceptance criteria:

• Every MCP Server and Virtual Server operation issued by the UI hits /v1/mcp-servers / /v1/virtual-servers
• grep -rn "['\"\]/gateways|['"`]/servers" src` (excluding the flagged connection-URL case, if kept legacy) returns nothing outside test fixtures
• Unit + e2e suites green
• No BFF proxy or SSE route changes required (confirm, don't assume)