feat: expose DB pool_size and max_overflow as env vars (P4)

Added AE_DB_POOL_SIZE and AE_DB_POOL_MAX_OVERFLOW to config.py with
defaults matching prior hardcoded values (10/20). Wired into settings.DB
property so create_ae_engine() reads them without fallback.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/config.py

@@ -27,6 +27,8 @@ class Settings(BaseSettings):
     # Connection tuning
     DB_CONNECT_TIMEOUT:  int = Field(20,   env='AE_DB_CONNECTION_TIMEOUT')
     DB_POOL_RECYCLE:     int = Field(1800, env='AE_DB_POOL_RECYCLE')
+    DB_POOL_SIZE:        int = Field(10,   env='AE_DB_POOL_SIZE')
+    DB_POOL_MAX_OVERFLOW: int = Field(20,  env='AE_DB_POOL_MAX_OVERFLOW')
 
     # --- Logging ---
     LOG_PATH_APP: str = Field('/logs/aether_api.log', env='AE_API_LOG_PATH')
@@ -75,6 +77,8 @@ class Settings(BaseSettings):
             'password':        self.DB_PASS,
             'connect_timeout':  self.DB_CONNECT_TIMEOUT,
             'pool_recycle':     self.DB_POOL_RECYCLE,
+            'pool_size':        self.DB_POOL_SIZE,
+            'max_overflow':     self.DB_POOL_MAX_OVERFLOW,
         }
 
     @property

documentation/TODO__Agents.md

@@ -19,7 +19,7 @@
 - [x] **[P1] Fix retry mechanism in `sql_update` / `run_sql_select`** — On `OperationalError`, both call `sql_connect()` → `reconnect_db()` which calls `engine.dispose()`, nuking the entire connection pool mid-flight. Under concurrent requests this kills other in-flight connections. Fix: remove the `sql_connect()` retry call; SQLAlchemy's `pool_pre_ping=True` already handles stale connections — just open a fresh `engine.connect()` for the retry without disposing the pool.
 - [ ] **[P2] Add retry logic to `sql_insert` and `sql_select`** — Both are missing the `OperationalError` retry that `sql_update` and `run_sql_select` have. A DB blip during an INSERT (scan record, badge log, etc.) fails silently and returns `False` with no recovery attempt.
 - [ ] **[P3] Guard `db = engine.connect()` in `lib_sql_core.py` with try/except** — Line 48 is a bare connect at module load time with no error handling. If MariaDB isn't ready (Docker race), this throws unhandled and crashes the worker. Wrap in try/except like `db_connection.py` already does.
-- [ ] **[P4] Expose `pool_size` / `max_overflow` as env vars** — `create_ae_engine()` calls `settings.DB.get('pool_size', 10)` but `settings.DB` property doesn't include those keys, so they're always hardcoded 10/20. Add `AE_DB_POOL_SIZE` / `AE_DB_POOL_MAX_OVERFLOW` to `config.py`.
+- [x] **[P4] Expose `pool_size` / `max_overflow` as env vars** — `create_ae_engine()` calls `settings.DB.get('pool_size', 10)` but `settings.DB` property doesn't include those keys, so they're always hardcoded 10/20. Add `AE_DB_POOL_SIZE` / `AE_DB_POOL_MAX_OVERFLOW` to `config.py`.
 
 ## 📋 Feature Tasks
 - [x] **Core Isolation:** Harden `apply_forced_account_filter` to Fail-Closed.