fix(ci): clear three base-reds on release/v3.8.51 — open-sse typecheck, docs provider count, agent-skills sync (#13216)

Merged after reconciling against the tip. The one conflict was `docs/reference/PROVIDER_REFERENCE.md`, a generated file — regenerated with `npm run gen:provider-reference` (358 unique IDs) rather than hand-merged.

The three base-reds this PR targets, re-checked on the reconciled tree:

- `check:docs-counts`: **exit 0** — provider count 356 → 358 in AGENTS.md, llm.txt, the i18n mirrors and the SVG diagrams was its last red
- `check:open-sse-typecheck`: OK, 0 errors
- `check:agent-skills-sync`: exit 0 (`skills/cli-tunnel/SKILL.md` → `tunnel create [type]`)
- `autoCombo.test.ts` under the mcp vitest config: 63/63
- ESLint over the changed files: exit 0

AGENTS.md, llm.txt and SKILL.md are agent-instruction surfaces; the operator approved them for this PR explicitly.

package.json

@@ -1,7 +1,7 @@
 {
   "name": "omniroute",
   "version": "3.8.51",
-  "description": "Unified AI router with 356 providers, RTK+Caveman compression, auto fallback, MCP/A2A, desktop, PWA, and OpenAI-compatible APIs.",
+  "description": "Unified AI router with 358 providers, RTK+Caveman compression, auto fallback, MCP/A2A, desktop, PWA, and OpenAI-compatible APIs.",
   "type": "module",
   "bin": {
     "omniroute": "bin/omniroute.mjs",