Redesign detector category and connected readouts

[bertona88]

What changed

• adds the eight requested detector types with stable IDs and explicit capability sets
• adds a deterministic detector measurement layer for intensity, weak-light photon rate, power, spatial maps, beam diameter, image-plane status, wavefront state, Stokes parameters, spectra, repetition rate, and pulse duration
• adds a mobile-first dark detector bench where a detector must be connected before its supported signal properties appear
• adds live source controls for power, beam diameter, wavelength, divergence, and pulsed/CW mode
• labels the general detector as an idealized composite instrument
• keeps the immutable prototype/ snapshot untouched
• adds model, interface, claims, and acceptance documentation
• adds automated detector tests and syntax-check scripts

Model boundary

This is a reduced-order detector subsystem at an explicit detector reference plane. It does not yet connect to the circuit graph or model detector noise, calibration, saturation, quantum efficiency, exposure, aperture clipping, or electrical response dynamics.

Validation

The branch includes Node tests covering detector identities, capability separation, deterministic maps, PMT photon-rate estimation, power, wavefront classification, polarization classification, spectra, general-detector coverage, CW pulse handling, and invalid inputs. Browser acceptance steps are documented in ACCEPTANCE_TESTS.md.