fix: serve SpessaSynth processor locally to avoid CDN version mismatch

- Download spessasynth_processor.min.js from CDN, serve as static file
- Change __SpessaSynthCDN to /static/js/services/
- Fix version mismatch between esm.sh library and CDN processor

app/static/js/services/soundfontPlayer.js

@@ -107,9 +107,12 @@
                 const bufCopy = buffer.slice(0);
                 await _synthInstance.soundBankManager.addSoundBank(bufCopy, sfId);
                 await _synthInstance.isReady;
-                // Force program 0 on channel 0 to activate loaded bank
-                this.controllerChange(0, 0, 0);
-                this.programChange(0, 0);
+                // Force bank+program select on all channels to activate loaded bank
+                for (let ch = 0; ch < 16; ch++) {
+                    try { _synthInstance.controllerChange(ch, 0, 0); } catch (e) {}
+                    try { _synthInstance.controllerChange(ch, 32, 0); } catch (e) {}
+                    try { _synthInstance.programChange(ch, 0); } catch (e) {}
+                }
                 _currentSfId = sfId;
                 console.log("[SonicSF] SoundFont loaded:", sfId);
             } catch (e) {