Add PrecompileTools workload to improve startup time

[ChrisRackauckas-Claude]

Summary

• Add PrecompileTools.jl as a dependency
• Add precompilation workload for common entry points (FVMGeometry, boundary conditions, FVMProblem, ODEProblem)
• Improves time-to-first-execution (TTFX) by 84%

Timing Measurements (Julia 1.10)

Before

Metric	Time
Package load time	1.046s
First FVMGeometry	0.108s
First BoundaryConditions	0.009s
First FVMProblem	0.065s
First ODEProblem	0.451s
Total TTFX	0.633s

After

Metric	Time	Improvement
Package load time	1.068s	-
First FVMGeometry	~0s	99%
First BoundaryConditions	~0s	99%
First FVMProblem	0.063s	-
First ODEProblem	0.036s	92%
Total TTFX	0.1s	84%

Note: FVMProblem TTFX is unchanged because user-provided functions (like diffusion_function) require runtime compilation - this is expected behavior.

Technical Details

• Precompilation time increased from ~2s to ~3s, which is acceptable given the significant TTFX improvements
• No invalidations were found from this package. The few invalidations detected during load come from dependencies (RecursiveArrayTools, SciMLBase, etc.)
• The precompilation workload uses minimal mesh sizes (10 points) to keep precompilation time low

Test plan

• Package loads correctly
• FVMProblem creation works
• ODEProblem creation works
• CI tests should pass (note: some image comparison tests may fail due to environment differences, unrelated to this PR)

cc @ChrisRackauckas

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