Rewrite hf-sim on the hf-simulation package

[lispandfound]

Replaces the hand-rolled Fortran deck writer and subprocess fan-out with
the hf-simulation package, and runs it per station chunk under dask so
a run is no longer bounded by one node's memory.

This changes every high-frequency result, principally through one
value.

corner_frequency_alpha was -99.0. That was never the physical
parameter: the Fortran deck reader treated anything below -1.0 as "use
the built-in default" (if(Calpha.lt.-1.0) Calpha = Calpha_default), so
-99.0 on disk meant 0.1. That decode lived in the deck reader, which
is gone. hf-simulation takes the value literally, and -99.0 drives
alpha_T negative for any fault that is not a vertical strike-slip. The
default is now 0.1, which is what the old configuration actually
computed with -- and is hf_simulation.SourceParameters' own default.

The hf realisation section is regrouped into source / path /
site / record to mirror hf_simulation.HfConfig group for group and
field for field, so it deserialises straight into that class instead of
being translated. That is deliberate: a translation layer between two
descriptions of the same physics is exactly the thing that drifts, and
this branch's history is largely a record of it having drifted. The
fields that used to be documented as "Unknown!" are gone -- they were
deck-format artefacts (nbu, ift, nl_skip, velocity_name,
ic_flag), zeroed uncertainty knobs, or values now computed rather than
configured.

Two of HfConfig's inputs are deliberately absent from the realisation.
record.duration_s is computed from the domain, and the
source.rupture_velocity multipliers live in RuptureVelocity because
SRF generation reads the same physical values -- one number, one home.
hf-sim injects both.

vs_moho moves from hf to hf_velocity_model_1d. It truncates the
velocity model at the Moho, which is a property of the model rather than
of the simulation.

Blocked on an hf-simulation release; currently a git dependency.

Co-Authored-By: Claude Opus 5 noreply@anthropic.com

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[github-actions]

Please change the following dependencies for consistency.

[github-actions]

Suggested change

	"hf-simulation @ git+https://github.com/ucgmsim/high-frequency",
	"hf-simulation @ git+https://github.com/ucgmsim/high-frequency.git",