Move the long-form documentation out of Doxygen and into a wiki-synced docs/ directory

[jakejackson1]

Moves the long-form documentation out of Doxygen and into eleven Markdown pages under docs/, published to the GitHub wiki by a new workflow.

The problem

The prose describing QueryPath lived in Doxygen DocBlocks and in src/documentation.php — 261 lines of @mainpage/@page markup and no runtime code, fed to Doxygen via config.doxy. It documented QueryPath 2, and a good deal of it had been wrong since QueryPath 3:

// What the documentation said:
$qp->find('p');   // "modifies the current object"

// What the code does:
$qp->find('p');          // returns a NEW DOMQuery; $qp is untouched
$qp->findInPlace('p');   // this is the mutating one — undocumented

Nothing published it, either. The wiki was hand-maintained and had drifted from both the DocBlocks and the code.

What's here

Page	Covers
Home	Wiki landing page
Getting-Started	Install, the three entry points, first queries
Parser-Options	Every option, and which parser honours it
CSS-Selector-Reference	Supported selectors, with the deviations called out
Writing-Extensions	The Extension interface and registration
API-Reference	All 99 public DOMQuery methods, alphabetical, plus a known-issues summary
Traversal-and-Filtering, Manipulation, Markup-and-Text, Document-and-Utility	The same methods grouped by job
How-to-parse-HTML-in-PHP-using-querypath-library	Existing wiki page, carried over

Wiki Sync publishes docs/ to the wiki on push to main. docs/ is the source of truth — the workflow replaces the wiki wholesale, so a page deleted here is deleted there, and edits made in the browser are overwritten. Cross-links keep their .md suffix in the repository (so they resolve when browsing the files here) and are stripped on the way to the wiki.

Verification

Every claim was checked by running the method, not by reading the DocBlock it came from. That turned up behaviour worth recording rather than quietly documenting around:

• The jQuery-style positional pseudo-classes (:eq, :lt, :gt, :nth) are 1-indexed, where jQuery's are 0-indexed
• remove() and replaceAll() go through the legacy selector engine, and disagree with find() on :lt(), :any-link and :scope
• css() pools style declarations across the whole match set and writes the union to every element in it
• not() inverts its test when given an SplObjectStorage; detach($selector) ignores its argument; hasAttr() returns true on an empty match set
• X > * raises a TypeError; writeHTML5() returns null and so cannot be chained
• filterLambda() and eachLambda() raise an Error on PHP 8 — both were built on the removed create_function()
• :indeterminate returns a random result; ::first-line/::first-letter return the whole element

DocBlocks that no longer described the code were corrected too: has() and sort() return a new object rather than mutating; size() claimed there is no $length property, but there is; childrenText() collects the whole subtree; dataURL()'s getter returns an array; branch() referred to a QPTPL class that does not exist.

Risk

Comments only. The diff over src/ — 28 files, 368 insertions, 828 deletions — contains no executable line; filtering it for non-comment content returns nothing. Suite unchanged at 319 tests, 1073 assertions; composer run lint clean.

No Doxygen-specific markup (@code/@endcode, @ingroup, @addtogroup, @attention, @retval, @b, inline <b>/<i>/<em>) remains in src/.

Conflicts with #70

The CHANGELOG entry and CSS-Selector-Reference here document the positional pseudo-classes as 1-indexed. #70 changes them to 0-indexed to match jQuery. Whichever lands second needs those reconciled — this branch documents the behaviour #70 replaces. Same for the note that remove()/replaceAll() disagree with find(), which #70 also fixes.

Notes

• docs/* was removed from .gitignore; it had been there for phpDocumentor HTML output committed years ago
• .claude/plans/modernization.md is a separate commit so it can be dropped independently — it's the 4.x audit behind this work, not documentation
• config.doxy is left in place; removing it is a separate call now that nothing generates from it

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.44%. Comparing base (296d828) to head (e9afeea).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##               main      #85   +/-   ##
=========================================
  Coverage     89.44%   89.44%           
  Complexity     1342     1342           
=========================================
  Files            26       26           
  Lines          3023     3023           
=========================================
  Hits           2704     2704           
  Misses          319      319           

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