fix(align.met): use length(stamps.hr) instead of stamps.hr as the rep() each argument

[anshul23102]

Summary

In the ensemble-source branch of align.met(), when the source dataset is at a coarser time step than the training data (align == "repeat"), source values must be repeated to match the finer training resolution. The original code was:

dat.tem <- rep(dat.tem, each = stamps.hr)

stamps.hr is a numeric vector of hour-of-day time stamps (e.g. c(1, 3, 5, ...) for 2-hourly data). Passing a vector to rep()'s each argument is silent in R -- the function uses only the first element and ignores the rest. The first element is hr.train / 2, a floating-point number that gets truncated to an integer, so the replication count is wrong.

The correct scalar to pass is length(stamps.hr) -- the number of output sub-steps that each coarser source value should fill. The equivalent code in the single-time-series branch of the same function (a few hundred lines earlier) already does this correctly:

dat.tem <- rep(dat.tem, each = length(stamps.hr))   # single-series path (correct)

The ensemble-source path was missing the length() call, producing silently corrupted met data with the wrong number of rows any time ensemble source data at a coarser temporal resolution was aligned with higher-resolution training data.

Change

• modules/data.atmosphere/R/align_met.R line 431: each = stamps.hr -> each = length(stamps.hr).
• modules/data.atmosphere/NEWS.md: added entry for the development version.

Test plan

• Call align.met() with ensemble source data at daily resolution and training data at sub-daily resolution (e.g. 3-hourly); confirm the number of rows in met.out$dat.source matches the training data time dimension.
• Confirm the aligned source values are repeated the correct number of times (e.g. a single daily value repeated 8 times for 3-hourly training data).
• Confirm the single-time-series path is unaffected.
• R CMD check on PEcAn.data.atmosphere passes without new warnings or errors.