Phase 3: AI integration with Ollama via Python sidecar

- sidecar: FastAPI app with /embed, /generate, /rerank hitting Ollama
- sidecar: Dockerfile, env var config (EMBED_MODEL, GEN_MODEL, RERANK_MODEL)
- aibridge: reqwest HTTP client with typed request/response structs
- aibridge: Axum proxy endpoints (POST /ai/embed, /ai/generate, /ai/rerank)
- gateway: wires AiClient with SIDECAR_URL env var
- e2e verified: nomic-embed-text returns 768d vectors, qwen2.5 generates text

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

sidecar/sidecar/ollama.py

@@ -0,0 +1,12 @@
+"""Shared Ollama HTTP client."""
+
+import os
+
+import httpx
+
+OLLAMA_URL = os.environ.get("OLLAMA_URL", "http://localhost:11434")
+TIMEOUT = float(os.environ.get("OLLAMA_TIMEOUT", "120"))
+
+
+def client() -> httpx.AsyncClient:
+    return httpx.AsyncClient(base_url=OLLAMA_URL, timeout=TIMEOUT)