Refresh README Example 2 values for the split zpe_fac/harm_fac scaling

The ethane_spc / ethane SPC examples in README and docs/source/README
were last regenerated under pre-refactor v3.x (zpe_fac applied
uniformly). The split scaling that landed in 4409b86 leaves ZPE
matching that pre-refactor value but shifts H_SPC, T·S, and G_SPC
by ~0.001 Hartree (those columns now use harm_fac for the vibrational
contribution while ZPE keeps zpe_fac).

Updated both README.md and docs/source/README.md (the latter is the
copy RTD serves; not auto-synced from the project root, so both need
the change). Also refreshed the explanatory text under Example 2 to
mention both factors (0.991 harmonic / 0.977 ZPE for B3LYP/6-31G(d))
and to point at --zpe-vscal for ZPE-only override.

Examples 7 and 8 are unchanged: they pass mixed levels of theory, so
auto-lookup falls back to 1.0 for both factors and the values are
identical to before.

Author: bobbypaton

README.md

@@ -99,11 +99,11 @@ goodvibes examples/ethane_spc.out --spc link
 
    Structure                E_SPC             E        ZPE         H_SPC        T.S     T.qh-S      G(T)_SPC   qh-G(T)_SPC
    ***********************************************************************************************************************
-o  ethane_spc          -79.858399    -79.830421   0.073508    -79.780448   0.027569   0.027570    -79.808017    -79.808019
+o  ethane_spc          -79.858399    -79.830421   0.073508    -79.779414   0.027540   0.027542    -79.806954    -79.806956
    ***********************************************************************************************************************
 ```
 
-This calculation contains a multi-step job: an optimization and frequency calculation with a small basis set followed by (--Link1--) a larger basis set single point energy. Note the use of the `--spc link` option. The standard harmonic and quasi-harmonic corrected thermochemical data are obtained from the small basis set partition function combined with the larger basis set single point electronic energy. In this example, GoodVibes automatically recognizes the level of theory used in the frequency calculation, B3LYP/6-31G(d), and applies the appropriate scaling factor of 0.977 (this can be suppressed to apply no scaling with -v 1.0)
+This calculation contains a multi-step job: an optimization and frequency calculation with a small basis set followed by (--Link1--) a larger basis set single point energy. Note the use of the `--spc link` option. The standard harmonic and quasi-harmonic corrected thermochemical data are obtained from the small basis set partition function combined with the larger basis set single point electronic energy. In this example, GoodVibes automatically recognizes the level of theory used in the frequency calculation, B3LYP/6-31G(d), and applies the [Truhlar group scaling factors](https://t1.chem.umn.edu/freqscale/index.html) of 0.991 (harmonic, used for H<sub>vib</sub> and S<sub>vib</sub>) and 0.977 (ZPE). Use `-v 1.0` to suppress all scaling, or `--zpe-vscal Y` to override only the ZPE factor.
 
 Alternatively, if a single point energy calculation has been performed separately, provided both file names share a common root e.g. `ethane.out` and `ethane_TZ.out` then use of the `--spc TZ` option is appropriate. This will give identical results as above.
 
@@ -112,7 +112,7 @@ goodvibes examples/ethane.out --spc TZ
 
    Structure                E_SPC             E        ZPE         H_SPC        T.S     T.qh-S      G(T)_SPC   qh-G(T)_SPC
    ***********************************************************************************************************************
-o  ethane              -79.858399    -79.830421   0.073508    -79.780448   0.027569   0.027570    -79.808017    -79.808019
+o  ethane              -79.858399    -79.830421   0.073508    -79.779414   0.027540   0.027542    -79.806954    -79.806956
    ***********************************************************************************************************************
 ```
 

docs/source/README.md

@@ -99,11 +99,11 @@ goodvibes examples/ethane_spc.out --spc link
 
    Structure                E_SPC             E        ZPE         H_SPC        T.S     T.qh-S      G(T)_SPC   qh-G(T)_SPC
    ***********************************************************************************************************************
-o  ethane_spc          -79.858399    -79.830421   0.073508    -79.780448   0.027569   0.027570    -79.808017    -79.808019
+o  ethane_spc          -79.858399    -79.830421   0.073508    -79.779414   0.027540   0.027542    -79.806954    -79.806956
    ***********************************************************************************************************************
 ```
 
-This calculation contains a multi-step job: an optimization and frequency calculation with a small basis set followed by (--Link1--) a larger basis set single point energy. Note the use of the `--spc link` option. The standard harmonic and quasi-harmonic corrected thermochemical data are obtained from the small basis set partition function combined with the larger basis set single point electronic energy. In this example, GoodVibes automatically recognizes the level of theory used in the frequency calculation, B3LYP/6-31G(d), and applies the appropriate scaling factor of 0.977 (this can be suppressed to apply no scaling with -v 1.0)
+This calculation contains a multi-step job: an optimization and frequency calculation with a small basis set followed by (--Link1--) a larger basis set single point energy. Note the use of the `--spc link` option. The standard harmonic and quasi-harmonic corrected thermochemical data are obtained from the small basis set partition function combined with the larger basis set single point electronic energy. In this example, GoodVibes automatically recognizes the level of theory used in the frequency calculation, B3LYP/6-31G(d), and applies the [Truhlar group scaling factors](https://t1.chem.umn.edu/freqscale/index.html) of 0.991 (harmonic, used for H<sub>vib</sub> and S<sub>vib</sub>) and 0.977 (ZPE). Use `-v 1.0` to suppress all scaling, or `--zpe-vscal Y` to override only the ZPE factor.
 
 Alternatively, if a single point energy calculation has been performed separately, provided both file names share a common root e.g. `ethane.out` and `ethane_TZ.out` then use of the `--spc TZ` option is appropriate. This will give identical results as above.
 
@@ -112,7 +112,7 @@ goodvibes examples/ethane.out --spc TZ
 
    Structure                E_SPC             E        ZPE         H_SPC        T.S     T.qh-S      G(T)_SPC   qh-G(T)_SPC
    ***********************************************************************************************************************
-o  ethane              -79.858399    -79.830421   0.073508    -79.780448   0.027569   0.027570    -79.808017    -79.808019
+o  ethane              -79.858399    -79.830421   0.073508    -79.779414   0.027540   0.027542    -79.806954    -79.806956
    ***********************************************************************************************************************
 ```