Add ChaisemartinDHaultfoeuille (dCDH) DID_M estimator (Phase 1) #925

Job	Run time
CI Gate	3s
Pure Python Fallback	1h 0m 29s
Rust Unit Tests (ubuntu-latest)	1m 15s
Rust Unit Tests (macos-latest)	1m 6s
Rust Unit Tests (ubuntu-24.04-arm)	1m 25s
Rust Unit Tests (windows-latest)	2m 5s
Python Tests (windows-latest, py3.11)	33m 50s
Python Tests (ubuntu-latest, py3.11)	35m 53s
Python Tests (ubuntu-24.04-arm, py3.13)	19m 9s
Python Tests (macos-latest, py3.14)	17m 33s
Python Tests (ubuntu-24.04-arm, py3.11)	19m 11s
Python Tests (windows-latest, py3.13)	27m 29s
Python Tests (macos-latest, py3.13)	19m 41s
Python Tests (ubuntu-latest, py3.14)	36m 22s
Python Tests (ubuntu-24.04-arm, py3.14)	19m 10s
Python Tests (macos-latest, py3.11)	17m 46s
Python Tests (windows-latest, py3.14)	37m 36s
Python Tests (ubuntu-latest, py3.13)	36m 30s
	6h 26m 33s

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