Add TypeScript migration, image resizing, media upload UX, and multimedia support

- Migrate static JS to TypeScript (static-ts/ → compiled to internal/api/static/)
- Add image resizing on upload: JPEG/PNG/WebP scaled to max 1920px at quality 80
- Extract shared upload logic into upload.go (saveUpload, saveResizedImage, saveResizedWebP)
- Add POST /media endpoint for drag-drop/paste media uploads with markdown ref return
- Add background music player with video/audio coordination (autoplay.ts)
- Add global nav, public feed, hashtags, visibility, Markdown rendering for entries
- Add Dockerfile stage for TypeScript compilation (static-ts-builder)
- Add goldmark, disintegration/imaging, golang.org/x/image dependencies

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/internal/api/journal.go

@@ -2,8 +2,8 @@ package api
 
 import (
 	"fmt"
-	"io"
 	"log/slog"
+	"mime/multipart"
 	"net/http"
 	"os"
 	"path/filepath"
@@ -20,10 +20,17 @@ const (
 )
 
 var allowedMIME = map[string]string{
-	"image/jpeg": ".jpg",
-	"image/png":  ".png",
-	"image/webp": ".webp",
-	"image/heic": ".heic",
+	"image/jpeg":  ".jpg",
+	"image/png":   ".png",
+	"image/webp":  ".webp",
+	"image/heic":  ".heic",
+	"image/gif":   ".gif",
+	"video/mp4":   ".mp4",
+	"video/webm":  ".webm",
+	"audio/mpeg":  ".mp3",
+	"audio/ogg":   ".ogg",
+	"audio/wav":   ".wav",
+	"audio/aac":   ".aac",
 }
 
 type JournalHandler struct {
@@ -108,51 +115,8 @@ func (h *JournalHandler) HandleUpdateEntry(w http.ResponseWriter, r *http.Reques
 		return
 	}
 
-	// Handle new image uploads
-	if r.MultipartForm != nil && r.MultipartForm.File != nil {
-		files := r.MultipartForm.File["images"]
-		for _, fh := range files {
-			if fh.Size == 0 || fh.Size > maxSingleImage {
-				continue
-			}
-			f, err := fh.Open()
-			if err != nil {
-				continue
-			}
-			buf := make([]byte, 512)
-			n, _ := f.Read(buf)
-			mime := http.DetectContentType(buf[:n])
-			ext, ok := allowedMIME[mime]
-			if !ok {
-				f.Close()
-				continue
-			}
-			filename := sanitizeFilename(entryID+"_"+fh.Filename) + ext
-			destPath := filepath.Join(h.uploadDir, filename)
-			out, err := os.Create(destPath)
-			if err != nil {
-				f.Close()
-				continue
-			}
-			if _, err := out.Write(buf[:n]); err != nil {
-				out.Close(); f.Close(); os.Remove(destPath)
-				continue
-			}
-			if _, err := io.Copy(out, f); err != nil {
-				out.Close(); f.Close(); os.Remove(destPath)
-				continue
-			}
-			out.Close()
-			f.Close()
-			img := domain.JournalImage{
-				EntryID: entryID, Filename: filename,
-				OriginalName: fh.Filename, MimeType: mime, SizeBytes: fh.Size,
-			}
-			if _, err := h.store.InsertImage(r.Context(), img); err != nil {
-				slog.Error("insert image", "entry_id", entryID, "err", err)
-				os.Remove(destPath)
-			}
-		}
+	if r.MultipartForm != nil {
+		h.saveJournalImages(r, entryID, r.MultipartForm.File["images"])
 	}
 
 	http.Redirect(w, r, "/days/"+existing.EntryDate, http.StatusSeeOther)
@@ -219,71 +183,56 @@ func (h *JournalHandler) HandleCreateEntry(w http.ResponseWriter, r *http.Reques
 		return
 	}
 
-	// Handle image uploads
-	if r.MultipartForm != nil && r.MultipartForm.File != nil {
-		files := r.MultipartForm.File["images"]
-		for _, fh := range files {
-			if fh.Size > maxSingleImage {
-				continue // skip oversized images silently
-			}
-			f, err := fh.Open()
-			if err != nil {
-				continue
-			}
-
-			// Detect MIME type from first 512 bytes
-			buf := make([]byte, 512)
-			n, _ := f.Read(buf)
-			mime := http.DetectContentType(buf[:n])
-			ext, ok := allowedMIME[mime]
-			if !ok {
-				f.Close()
-				continue
-			}
-
-			filename := saved.EntryID + "_" + fh.Filename
-			filename = sanitizeFilename(filename) + ext
-			destPath := filepath.Join(h.uploadDir, filename)
-
-			out, err := os.Create(destPath)
-			if err != nil {
-				f.Close()
-				continue
-			}
-
-			// Write already-read bytes + rest; clean up file on any write error
-			if _, err := out.Write(buf[:n]); err != nil {
-				out.Close()
-				f.Close()
-				os.Remove(destPath)
-				continue
-			}
-			if _, err := io.Copy(out, f); err != nil {
-				out.Close()
-				f.Close()
-				os.Remove(destPath)
-				continue
-			}
-			out.Close()
-			f.Close()
-
-			img := domain.JournalImage{
-				EntryID:      saved.EntryID,
-				Filename:     filename,
-				OriginalName: fh.Filename,
-				MimeType:     mime,
-				SizeBytes:    fh.Size,
-			}
-			if _, err := h.store.InsertImage(r.Context(), img); err != nil {
-				slog.Error("insert image", "entry_id", saved.EntryID, "filename", filename, "err", err)
-				os.Remove(destPath)
-			}
-		}
+	if r.MultipartForm != nil {
+		h.saveJournalImages(r, saved.EntryID, r.MultipartForm.File["images"])
 	}
 
 	http.Redirect(w, r, "/days/"+date, http.StatusSeeOther)
 }
 
+// saveJournalImages saves uploaded files for a journal entry, with image resizing.
+// Errors per file are logged and silently skipped so the entry is always saved.
+func (h *JournalHandler) saveJournalImages(r *http.Request, entryID string, files []*multipart.FileHeader) {
+	ctx := r.Context()
+	for _, fh := range files {
+		if fh.Size == 0 || fh.Size > maxSingleImage {
+			continue
+		}
+		f, err := fh.Open()
+		if err != nil {
+			continue
+		}
+
+		buf := make([]byte, 512)
+		n, _ := f.Read(buf)
+		mime := http.DetectContentType(buf[:n])
+		if _, ok := allowedMIME[mime]; !ok {
+			f.Close()
+			continue
+		}
+
+		baseName := sanitizeFilename(entryID + "_" + fh.Filename)
+		filename, err := saveUpload(h.uploadDir, baseName, mime, buf[:n], f)
+		f.Close()
+		if err != nil {
+			slog.Error("save upload", "entry_id", entryID, "err", err)
+			continue
+		}
+
+		img := domain.JournalImage{
+			EntryID:      entryID,
+			Filename:     filename,
+			OriginalName: fh.Filename,
+			MimeType:     mime,
+			SizeBytes:    fh.Size,
+		}
+		if _, err := h.store.InsertImage(ctx, img); err != nil {
+			slog.Error("insert image", "entry_id", entryID, "err", err)
+			os.Remove(filepath.Join(h.uploadDir, filename))
+		}
+	}
+}
+
 // sanitizeFilename strips path separators and non-printable characters.
 func sanitizeFilename(name string) string {
 	name = filepath.Base(name)