Add project scaffolding with fx DI, SQLite migrations, and healthcheck

- go.mod with git.eeqj.de/sneak/chat module
- internal packages: globals, logger, config, db, healthcheck, middleware, handlers, server
- SQLite database with embedded migration system (schema_migrations tracking)
- Migration 001: schema_migrations table
- Migration 002: channels table
- Config with chat-specific vars (MAX_HISTORY, SESSION_TIMEOUT, MAX_MESSAGE_SIZE, MOTD, SERVER_NAME, FEDERATION_KEY)
- Healthcheck endpoint at /.well-known/healthcheck.json
- Makefile, .gitignore
- cmd/chatd/main.go entry point

internal/handlers/handlers.go

@@ -0,0 +1,56 @@
+package handlers
+
+import (
+	"context"
+	"encoding/json"
+	"log/slog"
+	"net/http"
+
+	"git.eeqj.de/sneak/chat/internal/db"
+	"git.eeqj.de/sneak/chat/internal/globals"
+	"git.eeqj.de/sneak/chat/internal/healthcheck"
+	"git.eeqj.de/sneak/chat/internal/logger"
+	"go.uber.org/fx"
+)
+
+type HandlersParams struct {
+	fx.In
+	Logger      *logger.Logger
+	Globals     *globals.Globals
+	Database    *db.Database
+	Healthcheck *healthcheck.Healthcheck
+}
+
+type Handlers struct {
+	params *HandlersParams
+	log    *slog.Logger
+	hc     *healthcheck.Healthcheck
+}
+
+func New(lc fx.Lifecycle, params HandlersParams) (*Handlers, error) {
+	s := new(Handlers)
+	s.params = &params
+	s.log = params.Logger.Get()
+	s.hc = params.Healthcheck
+	lc.Append(fx.Hook{
+		OnStart: func(ctx context.Context) error {
+			return nil
+		},
+	})
+	return s, nil
+}
+
+func (s *Handlers) respondJSON(w http.ResponseWriter, r *http.Request, data interface{}, status int) {
+	w.WriteHeader(status)
+	w.Header().Set("Content-Type", "application/json")
+	if data != nil {
+		err := json.NewEncoder(w).Encode(data)
+		if err != nil {
+			s.log.Error("json encode error", "error", err)
+		}
+	}
+}
+
+func (s *Handlers) decodeJSON(w http.ResponseWriter, r *http.Request, v interface{}) error {
+	return json.NewDecoder(r.Body).Decode(v)
+}