Create a Hugo word-wrap helper partial at
`layouts/partials/helpers/terminal-wordwrap.html` that breaks text at word
boundaries with shell-style continuation support.

This will used by `images.Text` to generate open graph thumbnails at hugo site
build time, simulating a shell-prompt + output.

## Requirements

- The partial receives a dict with:
  - text (string) — the text to wrap
  - maxChars (int) — max characters per line
  - continuation (string, optional) — suffix appended to broken lines (e.g., \
    for shell line continuation)
  - padChars (int, optional) — number of characters to reserve for visual
    indentation on continuation lines (the indent itself is applied externally
    via pixel offset, since Hugo's `images.Text` strips leading whitespace)
- Returns a dict with:
  - firstLine (string) — the first line of wrapped text (including continuation
    suffix if it overflows)
  - rest (string) — remaining lines joined with \n (without padding — padding is
    handled by the caller at the pixel level)
  - lineCount (int) — total number of lines

## Key implementation detail

Use newScratch (Hugo's `collections.NewScratch`) with Set/Get/Add methods to
work around Go template variable scoping — variables reassigned inside range
blocks don't persist across iterations without a scratch pad.

### Why first line is returned separately

Hugo's `images.Text` filter uses strings.FieldsSeq (discards whitespace tokens)
and strings.TrimSpace on each line before rendering, making space-based
indentation impossible. The caller must render continuation lines as a separate
`images.Text` filter with an increased pixel x offset to achieve visual
indentation.