Use absolute enthalpy in df0DFoam solver

[Copilot]

C2H4 zero-D ignition was held near 2000 K because the solver used sensible enthalpy (hs), preventing chemical heat release from raising temperature.

• Energy definition: Set CanteraMixture::energyName to ha (absolute enthalpy) in df0DFoam to conserve total enthalpy during ignition.

Example:

// Ensure 0-D ignition tracks total enthalpy (incl. formation)
CanteraMixture::setEnergyName("ha");

Original prompt

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This section details on the original issue you should resolve

<issue_title>Incorrect result for C2H4 ignition problem in df0DFoam</issue_title>
<issue_description>- Fuel: C2H4

• Problem: Ignition at 2000K and 50e3Pa

• ha: Original treatment

• hs: Introduced in 0ad2411

Time	    ha	       hs
1.00E-06	2005.95	1999.98
2.00E-06	2011.92	1999.97
3.00E-06	2017.9	1999.96
4.00E-06	2023.9	1999.94
5.00E-06	2029.92	1999.93
6.00E-06	2035.94	1999.91
7.00E-06	2041.97	1999.9
8.00E-06	2048.01	1999.89
9.00E-06	2054.05	1999.87
1.00E-05	2060.09	1999.86
1.10E-05	2066.12	1999.85
1.20E-05	2072.16	1999.84
1.30E-05	2078.18	1999.83
1.40E-05	2084.18	1999.82
1.50E-05	2090.16	1999.81
1.60E-05	2096.11	1999.8
1.70E-05	2102.01	1999.79
1.80E-05	2107.84	1999.79
1.90E-05	2113.58	1999.79
2.00E-05	2119.17	1999.79
2.10E-05	2124.58	1999.8
2.20E-05	2129.76	1999.83
2.30E-05	2134.67	1999.87
2.40E-05	2139.31	1999.94
2.50E-05	2143.71	2000.04
2.60E-05	2147.96	2000.17
2.70E-05	2152.18	2000.34
2.80E-05	2156.47	2000.53
2.90E-05	2160.88	2000.71
3.00E-05	2165.39	2000.87
3.10E-05	2169.96	2000.99
3.20E-05	2174.57	2001.05
3.30E-05	2179.19	2001.06
3.40E-05	2183.79	2001.03
3.50E-05	2188.37	2000.95
3.60E-05	2192.92	2000.85
3.70E-05	2197.43	2000.73
3.80E-05	2201.9	2000.59

</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Incorrect result for C2H4 ignition problem in df0DFoam #576

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