Add alignment state indicator and pluggable data sources

- AlignmentThresholds dataclass + VisionEngine.__init__ for injection
- alignment_state computed per snapshot (ready/aligning/fault)
- MonitorPlot circle/vector/legend driven by state color
- Status dot + label moved into POSITION VISUALIZATION panel header
- CsvSessionSource + DemoSource pluggable DataSource layer
- Synthetic DATA/ready/ and DATA/aligning/ sessions for visual testing
- Fix CAM 3 label placement (below circle, not above)

DATA/0709/R10709P0.CSV

@@ -0,0 +1,61 @@
+# saved_on,DATA
+# master_file,R10709P0.CSV
+# remote_begin,BEGIN_REMOTE_CSV SOURCE=BOARD_REMOTE SPI=1 BIT=4 POINTS=51 MODE=ORDINARY STATUS=ERROR
+# source,BOARD_REMOTE
+# spi,SPI1
+# tick_ms,207407
+# bit,4
+# edge_mode,ORDINARY
+# points,51
+x,y
+240,28
+161,30
+206,31
+51,32
+278,32
+8,48
+49,50
+282,51
+207,62
+272,81
+122,86
+42,96
+80,98
+99,98
+209,98
+134,105
+247,110
+152,112
+35,121
+161,123
+292,127
+56,128
+237,128
+94,143
+268,162
+207,174
+221,182
+85,195
+2,200
+217,211
+42,215
+72,217
+147,217
+39,227
+275,230
+136,233
+125,243
+296,243
+209,249
+285,250
+245,258
+30,261
+26,277
+110,277
+299,290
+68,293
+30,297
+26,300
+36,305
+297,305
+21,318