fix: resolve QA report issues across routing, editor, i18n, and pipeline

- Add /tools/:toolId legacy redirect and catch-all 404 page (P1-12, P1-13)
- Add Shift+O dodge/burn/sponge cycle and Ctrl+Y redo shortcut (P1-3, P1-4)
- Fix Fit on Screen menu action to properly compute fit zoom (P1-8)
- Add filename input to editor export dialog (P1-2)
- Fix password validation mismatch: frontend now requires 8 chars (P1-11)
- Add license info to Settings About section (P1-9)
- Replace hardcoded strings in dropzone, files, pipeline with i18n keys (P1-17 to P1-25)
- Add 20+ missing i18n keys to all 21 locale files
- Translate Japanese editor.shapes and settings.aiFeatures sections (P1-19, P1-20)
- Fix RTL: use logical CSS properties in sidebar, files, app-layout (P2-24 to P2-26)
- Add single-file download button to pipeline results (P1-28)
- Fix compress step settings restoration on pipeline load (P1-27)
- Increase mobile nav touch targets to 44px minimum (P2-29)

apps/web/src/components/common/dropzone.tsx

@@ -264,7 +264,7 @@ export function Dropzone({
           <>
             <div className="flex items-center gap-2 w-full max-w-xs">
               <div className="h-px flex-1 bg-border" />
-              <span className="text-xs text-muted-foreground">or</span>
+              <span className="text-xs text-muted-foreground">{t.dropzone.orSeparator}</span>
               <div className="h-px flex-1 bg-border" />
             </div>
             <div className="flex gap-2 w-full max-w-sm">
@@ -295,7 +295,7 @@ export function Dropzone({
                 disabled={urlLoading || !urlInput.trim()}
                 className="rounded-md bg-primary px-3 py-1.5 text-sm font-medium text-primary-foreground hover:bg-primary/90 disabled:opacity-50"
               >
-                {urlLoading ? "..." : "Add"}
+                {urlLoading ? t.dropzone.urlLoadingIndicator : t.dropzone.addUrlButton}
               </button>
             </div>
             {urlError && <p className="text-xs text-destructive">{urlError}</p>}