Fix typos, grammar, and broken links across all chapters

[VincentGuyader]

What

Full proofreading pass over the 24 .Rmd source files of the book (~290 fixes):

• spelling mistakes and typos (pupepeteer, Icognito, upladed, Astonishmen, backgroud, {hemake}, {promise}, verbatimTextOuput, ...)
• grammar: subject-verb agreement, missing articles, singular/plural, "an bundled", "a software" (uncountable), "as follow"
• frenchisms: "allows to ", "divided in", "in term of", future tense in when-clauses, "the CRAN", "these two software", "in details", "50.000"
• doubled words ("even even", "Chapter 1, Chapter 1"), doubled periods, misplaced bold/italic markers
• three broken markdown links: js-cookie (malformed syntax), gremlins.js README (doubled parens), statnmap.com (rendered as a relative link)
• typos in code-chunk comments, including two comments saying "CSS file" where the code minifies shiny.js

Scope guarantees

• Prose and code comments only: no executable code, verbatim output block, chunk header/option, citation key, or cross-reference label was modified.
• The single in-code exception is browseURL("http:://localhost:2811") -> http:// in an eval = FALSE chunk.
• Insertions equal deletions in every file; the book's existing em-dash typography is untouched.
• Every hunk was verified by an independent review pass (markup balance, cross-refs, repo-wide leftover greps).

Deliberately NOT included: factual/technical errors spotted during the read (prose contradicting code examples, shinyapps.io described as on-premises, reversed cyclomatic-complexity formula, the building-ispum-app label, etc.). Those need author decisions and are listed separately for a follow-up.