feat(mcp): register web-session pool observability tools (#3368) (#4399)

The pool tools (omniroute_pool_status/sessions/reset/warm/health) shipped in
open-sse/mcp-server/tools/poolTools.ts but were never imported or registered in
server.ts, so they were defined-but-dead — the PR4 observability step of the
#3368 web-session roadmap was one wiring step from live.

Wire them through the standard registration loop (import + tool-count tally +
RESERVED_MCP_NAMES + Object.values(poolTools).forEach), add per-tool scopes
(read:health for status/sessions/health, write:resilience for reset/warm) to
both the inline tool defs and the canonical MCP_TOOL_SCOPES map. The forEach is
typed structurally (no new no-explicit-any) since the shape is pinned by tests.

Tests: extend mcp-tool-collections-shape with poolTools; add a dedicated guard
pinning the server.ts wiring (import/registration/reserved-name), the scope
contract (inline == MCP_TOOL_SCOPES, all in MCP_SCOPE_LIST), and live handler
behavior against the in-memory PoolRegistry.

src/shared/constants/mcpScopes.ts

@@ -65,6 +65,13 @@ export const MCP_TOOL_SCOPES: Record<string, readonly McpScope[]> = {
   omniroute_oneproxy_fetch: ["read:proxies"],
   omniroute_oneproxy_rotate: ["read:proxies"],
   omniroute_oneproxy_stats: ["read:proxies"],
+
+  // Web-session pool observability (read) + lifecycle (write)
+  omniroute_pool_status: ["read:health"],
+  omniroute_pool_sessions: ["read:health"],
+  omniroute_pool_health: ["read:health"],
+  omniroute_pool_reset: ["write:resilience"],
+  omniroute_pool_warm: ["write:resilience"],
 } as const;
 
 // ============ Scope Groups ============