refactor(cam): remove read noise from noise architecture (Phase 2)

- Make cam_read_noise a pass-through module, removing all noise injection logic
- Switch write noise to use noise_mask_bernoulli instead of noise_mask_grouped
- Add state machine to cam_write_noise for mask generation timing
- Remove noise_mask_grouped.sv (no longer needed)
- Remove read noise parameters from cam_noisy and cam_top
- Update simulation and benchmark code to reflect read noise removal
- Sync documentation to reflect Phase 2 architecture

hw/syn/synth_cam_top_flat.ys

@@ -10,7 +10,7 @@ verilog_defaults -add -I../rtl/random
 
 # Read RTL sources in canonical order
 read_verilog -sv -D SYNTHESIS ../rtl/random/random128.sv
-read_verilog -sv -D SYNTHESIS ../rtl/noise/noise_mask_grouped.sv
+read_verilog -sv -D SYNTHESIS ../rtl/noise/noise_mask_bernoulli.sv
 read_verilog -sv -D SYNTHESIS ../rtl/noise/cam_write_noise.sv
 read_verilog -sv -D SYNTHESIS ../rtl/noise/cam_read_noise.sv
 read_verilog -sv -D SYNTHESIS ../rtl/core/cam_core_banked.sv