supplier+deploy/mainnet: optional OPENAI_API_KEY for DeepSeek (and other hosted OpenAI-compatible APIs)

Adds an optional OPENAI_API_KEY env var that supplier/src/openai.ts forwards as
`Authorization: Bearer <key>`. Empty/unset preserves the ChatMock behaviour
(no auth header). Unlocks pointing the openai backend at DeepSeek directly
(https://api.deepseek.com) — no local proxy needed.

New compose: deploy/mainnet/docker-compose.supplier-deepseek.yml (third mainnet
supplier, model deepseek-v4-pro, mp-suppliers-deepseek.vector.apexfusion.org).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

deploy/mainnet/docker-compose.supplier-deepseek.yml

@@ -0,0 +1,81 @@
+# deploy/mainnet/docker-compose.supplier-deepseek.yml — Supplier — MAINNET (DeepSeek backend)
+#
+# Third mainnet supplier. LLM_BACKEND=openai pointed directly at DeepSeek's
+# hosted API (OpenAI-compatible at https://api.deepseek.com). No local proxy
+# container — DeepSeek is reachable over public HTTPS.
+#
+# Coexists with:
+#   - marketplace-mainnet-supplier      (ollama / qwen3.6:35b, mp-suppliers.vector.apexfusion.org)
+#   - marketplace-mainnet-supplier-gpt  (openai / ChatMock,   mp-suppliers-gpt.vector.apexfusion.org)
+#
+# Pre-flight:
+#   1. DNS A-record: mp-suppliers-deepseek.vector.apexfusion.org → host IP
+#   2. supplier/.env.deepseek written on host (chmod 600) with at minimum:
+#        SUPPLIER_PRIV_KEY_HEX, OPENAI_API_KEY, OGMIOS_URL, NETWORK_ID=1,
+#        VECTOR_ZERO_TIME_MS, ESCROW_REF_UTXO, ADVERT_REF_UTXO, ADVERT_REF,
+#        LIVE_CHAIN=1
+#   3. Networks already exist (created by the canonical supplier compose):
+#        docker network create marketplace-mainnet-net   # one-shot
+#        # traefik-net is created by the Traefik project
+
+name: marketplace-mainnet-supplier-deepseek
+
+services:
+  supplier:
+    build:
+      context: ../..
+      dockerfile: supplier/Dockerfile
+    container_name: marketplace-mainnet-supplier-deepseek
+    restart: unless-stopped
+    env_file:
+      # Self-contained env for the DeepSeek variant — separate from
+      # ../../supplier/.env (ollama-backed) and ../../supplier/.env.gpt
+      # (ChatMock-backed). Holds this supplier's distinct SUPPLIER_PRIV_KEY_HEX,
+      # ADVERT_REF, ADVERT_*, OPENAI_API_KEY, and the shared mainnet plumbing
+      # duplicated in full (NETWORK_ID, OGMIOS_URL, VECTOR_ZERO_TIME_MS,
+      # ref-script UTxOs, LIVE_CHAIN). No env_file ordering / override magic.
+      - path: ../../supplier/.env.deepseek
+        required: false
+    environment:
+      LLM_BACKEND: openai
+      # No /v1 suffix — supplier/src/openai.ts appends /v1/chat/completions.
+      OPENAI_BASE_URL: https://api.deepseek.com
+      # DeepSeek reasoning generations can be slow; mirror the GPT compose.
+      OPENAI_TIMEOUT_MS: "300000"
+      PORT: "8080"
+      # Enable LiveOgmiosProvider so submitTx/awaitTx actually broadcast.
+      # Without this the supplier silently falls back to ReadOnlyOgmiosProvider
+      # and Claim/Submit never reach chain.
+      LIVE_CHAIN: "1"
+      # NETWORK_ID and OGMIOS_URL intentionally not pinned here — they MUST
+      # come from the operator-provided supplier/.env.deepseek on a mainnet host.
+      # Setting them via compose would be a footgun: a stray re-up on
+      # testnet hardware could silently re-tag the supplier as mainnet.
+    healthcheck:
+      test: ["CMD-SHELL", "wget -qO- http://localhost:8080/healthz >/dev/null || exit 1"]
+      interval: 20s
+      timeout: 5s
+      retries: 3
+      start_period: 15s
+    networks:
+      - marketplace-mainnet-net
+      - traefik-net
+    labels:
+      - "traefik.enable=true"
+      - "traefik.docker.network=traefik-net"
+      - "traefik.http.routers.mp-suppliers-deepseek-mainnet.entrypoints=web"
+      - "traefik.http.routers.mp-suppliers-deepseek-mainnet.rule=Host(`mp-suppliers-deepseek.vector.apexfusion.org`)"
+      - "traefik.http.services.mp-suppliers-deepseek-mainnet.loadbalancer.server.port=8080"
+    logging:
+      driver: json-file
+      options:
+        max-size: "10m"
+        max-file: "3"
+
+networks:
+  marketplace-mainnet-net:
+    external: true
+    name: marketplace-mainnet-net
+  traefik-net:
+    external: true
+    name: traefik-net