[PierreRaybaut]

Follows #1 (merged).

Adds an Oscilloscope simulator... tool. It opens DataLab's instrument window (DataLab-Platform/DataLab#384, merged): live traces on the left, the settings on the right, and Acquire to add triggered shots to the workspace, ready for the Pulse methods.

• Source tab, chosen first: amplitude, amplitude and trigger jitter and pulse width, then the settings of a laser pulse (Gaussian or asymmetric, timing and amplitude drifts), an amplifier step response (second-order: natural frequency and damping ratio) or a two-channel pulse pair (detector delay, gain, width and jitter). Settings that do not apply to the chosen source are greyed out.
• Oscilloscope tab: time base, sample rate and trigger position; CH1 and CH2 scale and offset; ADC resolution (with clipping) and noise; triggers per acquisition and random seed.
• New core/oscilloscope.py (host-independent): channel screen ranges, time axis with the trigger at t = 0, digitization, sources and acquire_traces.
• Each acquisition goes to a new group such as "Oscilloscope - Pulse pair - acquisition 001", with shots titled CH1 shot 001 and the shot-number and channel metadata. A pulse-pair acquisition is ready for the two-channel delay method.
• Acquisitions are capped at 5 million samples; preview and acquisition use separate seed streams.
• The tool is declared in both the Desktop and Web adapters.

Tests

• 6 new unit tests, including the step overshoot (Ôëê 30.9 %) and the constant-fraction delay of the pulse pair; full suite: 113 passed.

Docs: new doc/oscilloscope-simulator.md, linked from the README and doc/simulation.md; CHANGELOG updated.

Assisted-by: Claude Opus 5.5