Add multi-database data layer

Introduce aether-data-schema and driver-specific schema generation for Postgres, MySQL, and SQLite.

Split data backends, lifecycle, repositories, and gateway runtime integration across database drivers.

Verified with cargo fmt --all --check, cargo clippy --workspace --all-targets -- -D warnings, and cargo test --workspace.

crates/aether-data/schema/generated/postgres/baseline/003_auth_config.sql

@@ -0,0 +1,85 @@
+-- Generated by aether-data-schema from schema/logical/*.toml.
+-- Do not edit generated files directly; edit logical schema or explicit overrides instead.
+
+CREATE TABLE IF NOT EXISTS public.system_configs (
+    id character varying(64) NOT NULL,
+    key character varying(255) NOT NULL,
+    value text NOT NULL,
+    description text,
+    created_at bigint NOT NULL,
+    updated_at bigint NOT NULL
+);
+
+ALTER TABLE ONLY public.system_configs ADD CONSTRAINT system_configs_pkey PRIMARY KEY (id);
+ALTER TABLE ONLY public.system_configs ADD CONSTRAINT system_configs_key_key UNIQUE (key);
+
+CREATE TABLE IF NOT EXISTS public.auth_modules (
+    id character varying(64) NOT NULL,
+    module_type character varying(128) NOT NULL,
+    enabled boolean DEFAULT true NOT NULL,
+    config jsonb NOT NULL,
+    created_at bigint NOT NULL,
+    updated_at bigint NOT NULL
+);
+
+ALTER TABLE ONLY public.auth_modules ADD CONSTRAINT auth_modules_pkey PRIMARY KEY (id);
+ALTER TABLE ONLY public.auth_modules ADD CONSTRAINT auth_modules_module_type_key UNIQUE (module_type);
+
+CREATE TABLE IF NOT EXISTS public.oauth_providers (
+    provider_type character varying(64) NOT NULL,
+    display_name character varying(255) NOT NULL,
+    client_id text NOT NULL,
+    client_secret_encrypted text,
+    authorization_url_override character varying(500),
+    token_url_override character varying(500),
+    userinfo_url_override character varying(500),
+    scopes jsonb,
+    redirect_uri character varying(500) NOT NULL,
+    frontend_callback_url character varying(500) NOT NULL,
+    attribute_mapping jsonb,
+    extra_config jsonb,
+    is_enabled boolean DEFAULT false NOT NULL,
+    created_at bigint NOT NULL,
+    updated_at bigint NOT NULL
+);
+
+ALTER TABLE ONLY public.oauth_providers ADD CONSTRAINT oauth_providers_pkey PRIMARY KEY (provider_type);
+
+CREATE TABLE IF NOT EXISTS public.ldap_configs (
+    id bigserial NOT NULL,
+    server_url character varying(255) NOT NULL,
+    bind_dn text NOT NULL,
+    bind_password_encrypted text,
+    base_dn text NOT NULL,
+    user_search_filter text DEFAULT '(uid={username})' NOT NULL,
+    username_attr character varying(50) DEFAULT 'uid' NOT NULL,
+    email_attr character varying(50) DEFAULT 'mail' NOT NULL,
+    display_name_attr character varying(50) DEFAULT 'cn' NOT NULL,
+    is_enabled boolean DEFAULT false NOT NULL,
+    is_exclusive boolean DEFAULT false NOT NULL,
+    use_starttls boolean DEFAULT false NOT NULL,
+    connect_timeout integer DEFAULT 10 NOT NULL,
+    created_at bigint NOT NULL,
+    updated_at bigint NOT NULL
+);
+
+ALTER TABLE ONLY public.ldap_configs ADD CONSTRAINT ldap_configs_pkey PRIMARY KEY (id);
+
+CREATE TABLE IF NOT EXISTS public.user_oauth_links (
+    id character varying(64) NOT NULL,
+    user_id character varying(64) NOT NULL,
+    provider_type character varying(64) NOT NULL,
+    provider_user_id character varying(255) NOT NULL,
+    provider_username character varying(255),
+    provider_email character varying(255),
+    extra_data jsonb,
+    linked_at bigint NOT NULL,
+    last_login_at bigint
+);
+
+ALTER TABLE ONLY public.user_oauth_links ADD CONSTRAINT user_oauth_links_pkey PRIMARY KEY (id);
+ALTER TABLE ONLY public.user_oauth_links ADD CONSTRAINT uq_user_oauth_links_provider_user UNIQUE (provider_type, provider_user_id);
+ALTER TABLE ONLY public.user_oauth_links ADD CONSTRAINT uq_user_oauth_links_user_provider UNIQUE (user_id, provider_type);
+CREATE INDEX IF NOT EXISTS user_oauth_links_provider_type_idx ON public.user_oauth_links USING btree (provider_type);
+CREATE INDEX IF NOT EXISTS user_oauth_links_user_id_idx ON public.user_oauth_links USING btree (user_id);
+