Support custom (interleaved) syndrome-extraction schedules in detector annotation

[Pritesh402]

annotate_detectors_automatically silently returned an incomplete set of detectors for circuits whose schedule interleaves collapsing operations with computation (e.g. a depth-optimized rotated surface code whose X-ancilla RX shares a moment with two-qubit gates, or whose Z/X ancillas are measured in separate moments). Such circuits pass is_valid_input_circuit but Fragment only collects leading resets / trailing measurements, and matching is consecutive- only, so interleaved collapsing ops are dropped and cross-round detectors are never found.

Add tqecd.schedule, which detects when a fragment would drop a collapsing op, rebuilds a logically-equivalent circuit with the canonical per-round shape, annotates it, and transplants the detectors back onto the original circuit (valid because the measurement record order is preserved). Circuits already handled correctly are left on the unchanged code path.

Issue creation is restricted, so opening as a PR.

[Copilot]

Pull request overview

This PR extends detector annotation to support circuits whose syndrome-extraction schedule interleaves collapsing operations (resets/measurements) with computation, by normalizing such circuits into a canonical per-round shape for annotation and then transplanting the resulting detectors back onto the original circuit.

Changes:

• Add tqecd.schedule to (1) detect when fragment splitting would drop interleaved collapsing ops, (2) canonicalize the schedule, and (3) transplant detectors back onto the original circuit.
• Update annotate_detectors_automatically to route affected circuits through the normalization + transplant path.
• Add a regression test and a new interleaved schedule .stim fixture demonstrating previously-dropped detectors.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
src/tqecd/test_files/valid/surface_code_rotated_memory_z_distance_3_interleaved_reset.stim	New fixture circuit with an interleaved reset schedule and expected detector annotations.
src/tqecd/schedule.py	New scheduling-normalization and detector-transplant implementation.
src/tqecd/schedule_test.py	Tests covering schedule detection, canonicalization record-order preservation, and recovered detectors.
src/tqecd/construction.py	Integrates normalization path into annotate_detectors_automatically.

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