Add a short Quarto vignette explaining the ABC algorithm

[Copilot]

Adds a compact vignette that explains how the package’s Artificial Bee Colony implementation works in practice. The new documentation stays close to the abc_optim() code path and includes a fresh optimization example not already covered in the package.

• New vignette

  • Adds vignettes/how-abc-works.qmd as a short Quarto-authored walkthrough of the algorithm.
  • Keeps the scope intentionally narrow: brief introduction, implementation-oriented explanation, and one concrete example.

• Algorithm walkthrough aligned with code

  • Describes the actual abc_optim() phases in order:
    • initialization of food sources
    • objective evaluation / fitness scoring
    • employed bee updates
    • onlooker selection and updates
    • best-source tracking and stopping rule
    • scout reinitialization
  • Calls out package-specific behavior such as bounded updates and the requirement that objective functions return a single finite numeric value.

• New example

  • Uses the Booth function instead of the objective functions already present in package examples.
  • Shows a small, reproducible abc_optim() run and resulting convergence trace.

booth <- function(x) {
  (x[1] + 2 * x[2] - 7)^2 + (2 * x[1] + x[2] - 5)^2
}

set.seed(2026)
ans <- abc_optim(
  par = c(0, 0),
  fn = booth,
  lb = -10,
  ub = 10,
  FoodNumber = 20,
  limit = 40,
  criter = 75,
  maxCycle = 500
)

• Quarto artifact hygiene
  • Adds a vignette-local .gitignore to avoid checking in Quarto-generated files.

• Fixes Write a short vignette that explains how the ABC algorithm works #8

[github-actions]

Version bump check ❌

group	base	head	bump
package	0.15.0-99	0.15.0-99	❌ not bumped

package — not bumped.

_{Checked 1 group(s) against 8bd66e5d3fec4916f32fedb538d2ea9de6fecc67 · please-bump}

[gvegayon]

@copilot, fix the GHA R-CMD-check-final

[github-actions]

Thank you for your contribution @gvegayon 🚀! The pkgdown site preview is ready for review 👉 Download here 👈!
_{(The artifact expires on 2026-12-09T20:02:58Z. You can re-generate it by re-running the workflow here.)}