Add Android control app and embedded server

Inspired by HNKServer/honoka-chan-apk-server, but implemented as a JNI-based embedded runtime instead of the original approach.

- Add an Android Compose controller app that starts and stops honoka-chan through JNI, shows runtime and health status, manages data directory mounting, and supports backup import/export for data.db
- Add an embeddable Go server entrypoint plus JNI-exported status, health, and reload hooks so desktop and Android builds share the same startup and shutdown path
- Add Android build scripts, runtime packaging, and project documentation, including generated default config.json content for honoka_runtime.zip
- Add runtime bundle hash tracking so updated honoka_runtime.zip assets are automatically redeployed while preserving config.json and user data files
- Add in-app service settings for unlock_all_special_rotation with immediate config persistence and automatic reload when the service is running
- Split SQLite driver selection by platform, using go-sqlite3 on Android and modernc.org/sqlite elsewhere to avoid Android x86_64 seccomp crashes
- Update startup, database initialization, and system health/reload handlers to support the embedded runtime and Android control flow

Signed-off-by: Sean Du <do4suki@gmail.com>

pkg/db/db.go

@@ -1,7 +1,7 @@
 package db
 
 import (
-	_ "modernc.org/sqlite"
+	"sync"
 	"xorm.io/xorm"
 )
 
@@ -10,37 +10,91 @@ var (
 	UserDb  = "assets/data.db"
 	MainEng *xorm.Engine
 	UserEng *xorm.Engine
+
+	mu sync.Mutex
 )
 
-func userSQLiteDSN(dbPath string) string {
-	return dbPath +
-		"?_pragma=busy_timeout(5000)" +
-		"&_pragma=journal_mode(WAL)" +
-		"&_pragma=synchronous(NORMAL)"
+func Init(mainDbPath, userDbPath string) error {
+	mu.Lock()
+	defer mu.Unlock()
+
+	if mainDbPath == "" {
+		mainDbPath = MainDb
+	}
+	if userDbPath == "" {
+		userDbPath = UserDb
+	}
+
+	if MainEng != nil || UserEng != nil {
+		if MainDb == mainDbPath && UserDb == userDbPath {
+			return nil
+		}
+		if err := closeLocked(); err != nil {
+			return err
+		}
+	}
+
+	mainEng, err := xorm.NewEngine(sqliteDriverName, mainSQLiteDSN(mainDbPath))
+	if err != nil {
+		return err
+	}
+	if err := prepareMainSQLiteEngine(mainEng); err != nil {
+		mainEng.Close()
+		return err
+	}
+	if err := mainEng.Ping(); err != nil {
+		mainEng.Close()
+		return err
+	}
+	mainEng.SetMaxOpenConns(10)
+	mainEng.SetMaxIdleConns(5)
+
+	userEng, err := xorm.NewEngine(sqliteDriverName, userSQLiteDSN(userDbPath))
+	if err != nil {
+		mainEng.Close()
+		return err
+	}
+	if err := prepareUserSQLiteEngine(userEng); err != nil {
+		mainEng.Close()
+		userEng.Close()
+		return err
+	}
+	if err := userEng.Ping(); err != nil {
+		mainEng.Close()
+		userEng.Close()
+		return err
+	}
+	userEng.SetMaxOpenConns(10)
+	userEng.SetMaxIdleConns(5)
+
+	MainDb = mainDbPath
+	UserDb = userDbPath
+	MainEng = mainEng
+	UserEng = userEng
+	return nil
 }
 
-func init() {
-	eng, err := xorm.NewEngine("sqlite", MainDb)
-	if err != nil {
-		panic(err)
+func Close() error {
+	mu.Lock()
+	defer mu.Unlock()
+	return closeLocked()
+}
+
+func closeLocked() error {
+	var firstErr error
+
+	if MainEng != nil {
+		if err := MainEng.Close(); err != nil && firstErr == nil {
+			firstErr = err
+		}
+		MainEng = nil
 	}
-	err = eng.Ping()
-	if err != nil {
-		panic(err)
+	if UserEng != nil {
+		if err := UserEng.Close(); err != nil && firstErr == nil {
+			firstErr = err
+		}
+		UserEng = nil
 	}
-	eng.SetMaxOpenConns(10)
-	eng.SetMaxIdleConns(5)
-	MainEng = eng
 
-	eng, err = xorm.NewEngine("sqlite", userSQLiteDSN(UserDb))
-	if err != nil {
-		panic(err)
-	}
-	err = eng.Ping()
-	if err != nil {
-		panic(err)
-	}
-	eng.SetMaxOpenConns(10)
-	eng.SetMaxIdleConns(5)
-	UserEng = eng
+	return firstErr
 }

pkg/db/sqlite_driver_android.go

@@ -0,0 +1,39 @@
+//go:build android
+
+package db
+
+import (
+	_ "github.com/mattn/go-sqlite3"
+	"xorm.io/xorm"
+)
+
+const sqliteDriverName = "sqlite3"
+
+func mainSQLiteDSN(dbPath string) string {
+	return dbPath
+}
+
+func userSQLiteDSN(dbPath string) string {
+	return dbPath
+}
+
+func prepareMainSQLiteEngine(engine *xorm.Engine) error {
+	return applySQLitePragmas(engine, nil)
+}
+
+func prepareUserSQLiteEngine(engine *xorm.Engine) error {
+	return applySQLitePragmas(engine, []string{
+		"PRAGMA busy_timeout = 5000",
+		"PRAGMA journal_mode = WAL",
+		"PRAGMA synchronous = NORMAL",
+	})
+}
+
+func applySQLitePragmas(engine *xorm.Engine, pragmas []string) error {
+	for _, pragma := range pragmas {
+		if _, err := engine.Exec(pragma); err != nil {
+			return err
+		}
+	}
+	return nil
+}

pkg/db/sqlite_driver_default.go

@@ -0,0 +1,29 @@
+//go:build !android
+
+package db
+
+import (
+	_ "modernc.org/sqlite"
+	"xorm.io/xorm"
+)
+
+const sqliteDriverName = "sqlite"
+
+func mainSQLiteDSN(dbPath string) string {
+	return dbPath
+}
+
+func userSQLiteDSN(dbPath string) string {
+	return dbPath +
+		"?_pragma=busy_timeout(5000)" +
+		"&_pragma=journal_mode(WAL)" +
+		"&_pragma=synchronous(NORMAL)"
+}
+
+func prepareMainSQLiteEngine(*xorm.Engine) error {
+	return nil
+}
+
+func prepareUserSQLiteEngine(*xorm.Engine) error {
+	return nil
+}