app: add code for macOS and Windows apps under 'app' (#12933)

* app: add code for macOS and Windows apps under 'app'

* app: add readme

* app: windows and linux only for now

* ci: fix ui CI validation

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Co-authored-by: jmorganca <jmorganca@gmail.com>

app/store/testdata/schema.sql

@@ -0,0 +1,61 @@
+-- This is the version 2 schema for the app database, the first released schema to users.
+-- Do not modify this file. It is used to test that the database schema stays in a consistent state between schema migrations.
+
+CREATE TABLE IF NOT EXISTS settings (
+    id INTEGER PRIMARY KEY CHECK (id = 1),
+    device_id TEXT NOT NULL DEFAULT '',
+    has_completed_first_run BOOLEAN NOT NULL DEFAULT 0,
+    expose BOOLEAN NOT NULL DEFAULT 0,
+    survey BOOLEAN NOT NULL DEFAULT TRUE,
+    browser BOOLEAN NOT NULL DEFAULT 0,
+    models TEXT NOT NULL DEFAULT '',
+    remote TEXT NOT NULL DEFAULT '',
+    agent BOOLEAN NOT NULL DEFAULT 0,
+    tools BOOLEAN NOT NULL DEFAULT 0,
+    working_dir TEXT NOT NULL DEFAULT '',
+    context_length INTEGER NOT NULL DEFAULT 4096,
+    window_width INTEGER NOT NULL DEFAULT 0,
+    window_height INTEGER NOT NULL DEFAULT 0,
+    config_migrated BOOLEAN NOT NULL DEFAULT 0,
+    schema_version INTEGER NOT NULL DEFAULT 2
+);
+
+-- Insert default settings row if it doesn't exist
+INSERT OR IGNORE INTO settings (id) VALUES (1);
+
+CREATE TABLE IF NOT EXISTS chats (
+    id TEXT PRIMARY KEY,
+    title TEXT NOT NULL DEFAULT '',
+    created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP
+);
+
+CREATE TABLE IF NOT EXISTS messages (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    chat_id TEXT NOT NULL,
+    role TEXT NOT NULL,
+    content TEXT NOT NULL DEFAULT '',
+    thinking TEXT NOT NULL DEFAULT '',
+    stream BOOLEAN NOT NULL DEFAULT 0,
+    model_name TEXT,
+    model_cloud BOOLEAN,
+    model_ollama_host BOOLEAN,
+    created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    updated_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    thinking_time_start TIMESTAMP,
+    thinking_time_end TIMESTAMP,
+    FOREIGN KEY (chat_id) REFERENCES chats(id) ON DELETE CASCADE
+);
+
+CREATE INDEX IF NOT EXISTS idx_messages_chat_id ON messages(chat_id);
+
+CREATE TABLE IF NOT EXISTS tool_calls (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    message_id INTEGER NOT NULL,
+    type TEXT NOT NULL,
+    function_name TEXT NOT NULL,
+    function_arguments TEXT NOT NULL,
+    function_result TEXT,
+    FOREIGN KEY (message_id) REFERENCES messages(id) ON DELETE CASCADE
+);
+
+CREATE INDEX IF NOT EXISTS idx_tool_calls_message_id ON tool_calls(message_id);