R1: Dashboard 500 fix, Phase 2/7 uncommitted changes

- Fix dashboard 500 when deps disconnected — _gather_state() now returns
  full defaults instead of bare {'connected': False}
- Phase 2: FX param schemas aligned with DSP implementations
- Phase 7: Pipeline routing, preset manager improvements
- Factory presets: cleanup and normalization

Fixes dashboard crash on disconnected state (dogfood issue #1)

presets/factory/bank_1/preset_3.json

@@ -6,11 +6,10 @@
   "tuner_enabled": false,
   "chain": [
     {"fx_type": "compressor", "enabled": true, "bypass": false, "params": {"threshold": 0.3, "ratio": 4.0, "gain": 0.9}, "nam_model_path": "", "ir_file_path": ""},
-    {"fx_type": "nam_amp", "enabled": true, "bypass": false, "params": {}, "nam_model_path": "factory/fender_twin.nam", "ir_file_path": ""},
-    {"fx_type": "ir_cab", "enabled": true, "bypass": false, "params": {}, "nam_model_path": "", "ir_file_path": "factory/american_2x12.wav"},
     {"fx_type": "phaser", "enabled": true, "bypass": false, "params": {"rate": 0.2, "depth": 0.6, "feedback": 0.4}, "nam_model_path": "", "ir_file_path": ""},
     {"fx_type": "chorus", "enabled": true, "bypass": false, "params": {"rate": 0.3, "depth": 0.7, "mix": 0.5}, "nam_model_path": "", "ir_file_path": ""},
     {"fx_type": "delay", "enabled": true, "bypass": false, "params": {"time": 500.0, "feedback": 0.4, "mix": 0.35}, "nam_model_path": "", "ir_file_path": ""},
+    {"fx_type": "ir_cab", "enabled": true, "bypass": false, "params": {"wet": 1.0, "dry": 0.0}, "nam_model_path": "", "ir_file_path": "~/.pedal/irs/american-2x12.wav"},
     {"fx_type": "reverb", "enabled": true, "bypass": false, "params": {"decay": 0.8, "mix": 0.4}, "nam_model_path": "", "ir_file_path": ""},
     {"fx_type": "volume", "enabled": true, "bypass": false, "params": {"level": 0.78}, "nam_model_path": "", "ir_file_path": ""}
   ],