feat(core): add configuration, logging and sqlite persistence

DB_PATH, HTTP_ADDR, HTTP_PORT and LOG_LEVEL parsing with validation; slog text logger with a TRACE level and token redaction; embedded idempotent schema on CGO-free SQLite (WAL, busy timeout); token store (create, list, deactivate, authenticate) and append-only audit store with ordered, limited and windowed queries; shared unit test helpers.

schema.sql

@@ -0,0 +1,18 @@
+-- SPDX-License-Identifier: GPL-2.0-or-later
+-- Copyright (C) 2026 Bryan Joshua Pedini
+
+CREATE TABLE IF NOT EXISTS tokens (
+    token       TEXT PRIMARY KEY NOT NULL,
+    description TEXT NOT NULL DEFAULT '',
+    active      INTEGER NOT NULL CHECK (active IN (0, 1)),
+    created_at  TEXT NOT NULL,
+    deleted_at  TEXT NULL
+);
+
+CREATE TABLE IF NOT EXISTS operations (
+    token     TEXT NOT NULL,
+    origin    TEXT NOT NULL,
+    operation TEXT NOT NULL,
+    time      TEXT NOT NULL,
+    FOREIGN KEY (token) REFERENCES tokens(token)
+);