[chore] media pipeline improvements (#3110)

* don't set emoji / media image paths on failed download, migrate FileType from string to integer

* fix incorrect uses of util.PtrOr, fix returned frontend media

* fix migration not setting arguments correctly in where clause

* fix not providing default with not null column

* whoops

* ensure a default gets set for media attachment file type

* remove the exclusive flag from writing files in disk storage

* rename PtrOr -> PtrOrZero, and rename PtrValueOr -> PtrOrValue to match

* slight wording changes

* use singular / plural word forms (no parentheses), is better for screen readers

* update testmodels with unknown media type to have unset file details, update attachment focus handling converting to frontend, update tests

* store first instance in ffmpeg wasm pool, fill remaining with closed instances

internal/storage/storage.go

@@ -26,7 +26,6 @@ import (
 	"net/url"
 	"os"
 	"path"
-	"syscall"
 	"time"
 
 	"codeberg.org/gruf/go-bytesize"
@@ -245,13 +244,9 @@ func NewFileStorage() (*Driver, error) {
 	// Load runtime configuration
 	basePath := config.GetStorageLocalBasePath()
 
-	// Use default disk config but with
-	// increased write buffer size and
-	// 'exclusive' bit sets when creating
-	// files to ensure we don't overwrite
-	// existing files unless intending to.
+	// Use default disk config with
+	// increased write buffer size.
 	diskCfg := disk.DefaultConfig()
-	diskCfg.OpenWrite.Flags |= syscall.O_EXCL
 	diskCfg.WriteBufSize = int(16 * bytesize.KiB)
 
 	// Open the disk storage implementation