fix(deploy): prevent Docker ENV vars from overriding JSON config

The root cause: Go's env.Parse() in LoadConfig reads PICOCLAW_*
environment variables AFTER loading config.json, silently overwriting
user-provided values. Dockerfile.coolify had hardcoded Gemini defaults
(PICOCLAW_AGENTS_DEFAULTS_PROVIDER=gemini) baked into the image layer,
so even when config.json correctly said 'vllm', the env vars won.

Fix:
- entrypoint-coolify.sh: When using PICOCLAW_CONFIG_JSON (Method 1), or
  mounted config (Method 2), unset all PICOCLAW_* env vars before
  calling picoclaw so the JSON file is the single source of truth.
- docker-compose-coolify.yml: Remove hardcoded gemini defaults from
  agent and doctor services.
- Updated docs header to recommend PICOCLAW_CONFIG_JSON as primary.

docker-compose-coolify.yml

@@ -9,12 +9,15 @@
 #   4. Add environment variables in Coolify's UI (see below)
 #   5. Deploy!
 #
-# REQUIRED ENVIRONMENT VARIABLES (set in Coolify UI):
+# RECOMMENDED: Use PICOCLAW_CONFIG_JSON for full control:
+#   PICOCLAW_CONFIG_JSON    — Full JSON config (overrides everything below)
+#
+# ALTERNATIVE: Individual environment variables:
 #   GEMINI_API_KEY          — Your Gemini API key
 #
 # OPTIONAL ENVIRONMENT VARIABLES:
-#   LLM_PROVIDER            — LLM provider (default: gemini)
+#   LLM_PROVIDER            — LLM provider (e.g. gemini, vllm, openrouter)
-#   LLM_MODEL               — Model name (default: gemini-2.5-flash-lite)
+#   LLM_MODEL               — Model name (e.g. gemini-2.5-flash-lite)
 #   TELEGRAM_BOT_TOKEN      — Telegram bot token
 #   DISCORD_BOT_TOKEN       — Discord bot token
 #   OPENROUTER_API_KEY      — OpenRouter API key
@@ -124,8 +127,8 @@ services:
     profiles:
       - agent
     environment:
-      - PICOCLAW_AGENTS_DEFAULTS_PROVIDER=${LLM_PROVIDER:-gemini}
+      - PICOCLAW_AGENTS_DEFAULTS_PROVIDER=${LLM_PROVIDER:-}
-      - PICOCLAW_AGENTS_DEFAULTS_MODEL=${LLM_MODEL:-gemini-2.5-flash-lite}
+      - PICOCLAW_AGENTS_DEFAULTS_MODEL=${LLM_MODEL:-}
       - PICOCLAW_PROVIDERS_GEMINI_API_KEY=${GEMINI_API_KEY:-}
       - PICOCLAW_PROVIDERS_OPENROUTER_API_KEY=${OPENROUTER_API_KEY:-}
       - PICOCLAW_PROVIDERS_OPENAI_API_KEY=${OPENAI_API_KEY:-}
@@ -151,8 +154,8 @@ services:
     profiles:
       - doctor
     environment:
-      - PICOCLAW_AGENTS_DEFAULTS_PROVIDER=${LLM_PROVIDER:-gemini}
+      - PICOCLAW_AGENTS_DEFAULTS_PROVIDER=${LLM_PROVIDER:-}
-      - PICOCLAW_AGENTS_DEFAULTS_MODEL=${LLM_MODEL:-gemini-2.5-flash-lite}
+      - PICOCLAW_AGENTS_DEFAULTS_MODEL=${LLM_MODEL:-}
       - PICOCLAW_PROVIDERS_GEMINI_API_KEY=${GEMINI_API_KEY:-}
       - TZ=${TZ:-UTC}
     volumes:

entrypoint-coolify.sh

@@ -23,6 +23,17 @@ mkdir -p "${CONFIG_DIR}"
 if [ -n "${PICOCLAW_CONFIG_JSON}" ]; then
   echo "📝 Using config from PICOCLAW_CONFIG_JSON env var"
   echo "${PICOCLAW_CONFIG_JSON}" > "${CONFIG_FILE}"
+
+  # CRITICAL: Unset all PICOCLAW_* env vars (except PICOCLAW_CONFIG_JSON)
+  # so that Go's env.Parse() does NOT override values from the JSON file.
+  # Without this, Dockerfile ENV defaults (e.g. PICOCLAW_AGENTS_DEFAULTS_PROVIDER=gemini)
+  # would silently overwrite the user's JSON config every time.
+  for var in $(env | grep '^PICOCLAW_' | cut -d= -f1); do
+    if [ "$var" != "PICOCLAW_CONFIG_JSON" ]; then
+      unset "$var"
+    fi
+  done
+
   exec picoclaw "$@"
 fi
 
@@ -36,6 +47,12 @@ fi
 if [ -f "/config/config.json" ]; then
   echo "📝 Using mounted config from /config/config.json"
   cp /config/config.json "${CONFIG_FILE}"
+
+  # Same protection as Method 1: unset PICOCLAW_* env vars
+  for var in $(env | grep '^PICOCLAW_' | cut -d= -f1); do
+    unset "$var"
+  done
+
   exec picoclaw "$@"
 fi