tp_compile() gives no guidance when a method name has been renamed across tpplc versions

[maribraga]

Environment

• treepplr 0.14.0
• tpplc 0.4

Issue

Older code/docs/vignettes (and existing analysis scaffolds we were working from) use method names like "mcmc-lightweight" and "is-lw". Neither exists in tpplc 0.4 — the current names are "mcmc" ("MCMC using the lightweight approach", per tpplc --help) and "is" ("Importance sampling using likelihood weights").

tp_compile(model_path, method = "mcmc-lightweight", iterations = 10L)
#> Error in compilation(m$path, options_to_string(full_options)) :
#>   Compilation failed

The only way to discover the actual problem is to run tpplc --help directly and diff the method list by hand — tp_compile()'s error gives no hint that method specifically is the issue, let alone what the valid values are.

Suggested fix

• Validate method against the known set of inference methods (is, smc-apf, smc-bpf, mcmc, mcmc-naive, mcmc-trace, mcmc-graph, pmcmc-pimh, per current tpplc --help) before compiling, and raise a clear R error listing valid options if it doesn't match.
• Surface the underlying tpplc command's actual stderr on compile failure by default (or via a verbose = TRUE argument) rather than the generic "Compilation failed", so the real reason (e.g. an unrecognized flag/value) is visible without having to reach into treepplr:::compilation() internals.