fix: shared config loads root .env as fallback for microservices

shared/config.py

@@ -4,11 +4,18 @@ All services import ``settings`` from here.  Each service only uses a subset
 of the vars, but keeping one Settings class avoids fragmentation.
 """
 
+from pathlib import Path
 from typing import Literal
 
 from pydantic import field_validator
 from pydantic_settings import BaseSettings, SettingsConfigDict
 
+# Locate the repo root (adiuva-api/) so we can load its .env as a fallback.
+# Works whether cwd is adiuva-api/ (monolith) or adiuva-api/services/xyz/ (microservice).
+_this_dir = Path(__file__).resolve().parent  # shared/
+_repo_root = _this_dir.parent               # adiuva-api/
+_root_env = _repo_root / ".env"
+
 
 class Settings(BaseSettings):
     # ── Database ─────────────────────────────────────────────────────
@@ -57,7 +64,6 @@ class Settings(BaseSettings):
     CEREBRAS_API_KEY: str = ""
 
     LLM_MODEL: str = "gpt-4o"
-    LLM_ROUTER_MODEL: str = "gpt-4o-mini"
     LLM_EMBED_MODEL: str = "text-embedding-3-small"
 
     GITHUB_COPILOT_TOKEN_DIR: str = ""
@@ -77,7 +83,10 @@ class Settings(BaseSettings):
     ENV: Literal["dev", "prod"] = "dev"
 
     model_config = SettingsConfigDict(
-        env_file=".env", env_file_encoding="utf-8", extra="ignore"
+        # Local .env (cwd) takes priority; root .env is fallback.
+        env_file=(".env", str(_root_env)),
+        env_file_encoding="utf-8",
+        extra="ignore",
     )