feat(gmw): route all LLM traffic through 9router

GMW moves off omniroute (100.121.180.82:20128) and off the direct NVIDIA
vision endpoint onto 9router, which runs on the same host as both services
(127.0.0.1:4014) — loopback avoids the TLS/proxy hop and localhost calls
bypass 9router's remote-key guard.

- gateway + backend: AI_LLM_BASE_URL default -> http://127.0.0.1:4014/v1
- drop stale 'omniroute' router references from comments/docs now that the
  active router is 9router (llmClient, llmCaller, ARCHITECTURE, AGENTS)

Verified against 9router before wiring: model 'text' -> gemini-3.5-flash-lite
(SSE, as the pipeline expects), 'multimodal' -> nemotron-3-nano-omni answers
image input, and gemini/gemini-embedding-001 returns 3072 dims — matching the
existing Qdrant collections (no reindex needed). The GMW key is already
registered in 9router's apiKeys table.

typecheck + lint + tests green (gateway 138, backend 37 excluding e2e).

services/discord-gateway/src/modules/ai-moderation/llmClient.ts

@@ -131,7 +131,7 @@ type LLMResponseChunk = {
  * `delta.content`; falls back to reasoning fields so reasoning-only models
  * still produce usable aggregated text. Providers differ in the field name:
  * - DeepSeek-style / Cloudflare gemma → `delta.reasoning_content`
- * - mimo (via omniroute) streams reasoning in `delta.reasoning` +
+ * - mimo (via the router) streams reasoning in `delta.reasoning` +
  *   `delta.reasoning_details[].text` (content:"") — without these fallbacks
  *   vision aggregation came back empty ("Vision API null response").
  * Exported for unit tests.
@@ -267,7 +267,7 @@ export function buildLlmParams(
       reasoning: { enabled: false },
       // vLLM / Qwen / litellm
       chat_template_kwargs: { enable_thinking: false },
-      // Anthropic / Claude-format (omniroute exposes thinkingFormat
+      // Anthropic / Claude-format (router exposes thinkingFormat
       // "claude-adaptive" / "claude-budget" on its reasoning models)
       thinking: { type: "disabled" },
     } as Record<string, unknown>);