Refactor the entire lesson structure

[huangsam]

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Describe the change
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Refactor the entire lesson structure.

Additional context
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The content has gotten to the point where advanced is becoming a place where "anything" just goes inside. And syntax isn't fully serving newcomers well. Time to make a rehaul to get things back on track again. Furthermore, the additional resources section across READMEs needed some pruning so that it remains relevant for users. This is basically v2 of the content so that the whole repo, including the brand new UI, is useful for users.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.55%. Comparing base (ef77187) to head (69b5323).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #185   +/-   ##
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  Coverage   99.55%   99.55%           
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  Files          43       43           
  Lines        1778     1778           
  Branches      113      113           
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  Hits         1770     1770           
  Misses          4        4           
  Partials        4        4           

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[Copilot]

Pull request overview

Refactors the curriculum/lesson structure by introducing new top-level lesson categories (e.g., fundamentals, oop, stdlib, concurrency, engineering) and updating the UI + READMEs to reflect the new organization.

Changes:

• Added/organized many new lesson modules under the new category folders.
• Updated lesson parsing + sidebar ordering + i18n labels to match the new taxonomy.
• Updated README curriculum outlines across multiple translations to reflect the new structure.

Reviewed changes

Copilot reviewed 18 out of 59 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
ultimatepython/stdlib/regex.py	Adds a new stdlib regex lesson module.
ultimatepython/stdlib/file_handling.py	Adds a stdlib file-handling lesson (open/pathlib).
ultimatepython/stdlib/date_time.py	Adds a stdlib datetime/timezone lesson.
ultimatepython/stdlib/data_format.py	Adds a stdlib JSON/XML/CSV parsing lesson.
ultimatepython/stdlib/init.py	Introduces stdlib package marker/docstring.
ultimatepython/oop/mro.py	Adds OOP method resolution order lesson.
ultimatepython/oop/mixin.py	Adds OOP mixin patterns lesson.
ultimatepython/oop/iterator_class.py	Adds OOP iterator-class vs generator lesson.
ultimatepython/oop/inheritance.py	Adds OOP inheritance lesson.
ultimatepython/oop/exception_class.py	Adds OOP custom exception class lesson.
ultimatepython/oop/encapsulation.py	Adds OOP encapsulation lesson (private attrs).
ultimatepython/oop/basic_class.py	Adds OOP basic class/instance introspection lesson.
ultimatepython/oop/abstract_class.py	Adds OOP abstract base class lesson.
ultimatepython/oop/init.py	Introduces OOP package marker/docstring.
ultimatepython/fundamentals/variable.py	Adds fundamentals variables/types lesson.
ultimatepython/fundamentals/expression.py	Adds fundamentals expressions/operators lesson.
ultimatepython/fundamentals/string.py	Adds fundamentals strings lesson.
ultimatepython/fundamentals/list.py	Adds fundamentals lists lesson.
ultimatepython/fundamentals/tuple.py	Adds fundamentals tuples lesson.
ultimatepython/fundamentals/set.py	Adds fundamentals sets lesson.
ultimatepython/fundamentals/dict.py	Adds fundamentals dicts lesson.
ultimatepython/fundamentals/conditional.py	Adds fundamentals conditionals lesson.
ultimatepython/fundamentals/loop.py	Adds fundamentals loops lesson.
ultimatepython/fundamentals/function.py	Adds fundamentals functions lesson.
ultimatepython/fundamentals/comprehension.py	Adds fundamentals comprehensions lesson.
ultimatepython/fundamentals/init.py	Introduces fundamentals package marker/docstring.
ultimatepython/engineering/namedtuple.py	Adds engineering namedtuple lesson.
ultimatepython/engineering/mocking.py	Adds engineering mocking lesson.
ultimatepython/engineering/itertools.py	Adds engineering itertools lesson.
ultimatepython/engineering/heap.py	Adds engineering heapq lesson.
ultimatepython/engineering/dict_union.py	Adds engineering dict union operators lesson.
ultimatepython/engineering/deque.py	Adds engineering deque lesson.
ultimatepython/engineering/defaultdict.py	Adds engineering defaultdict lesson.
ultimatepython/engineering/bitwise.py	Adds engineering bitwise operators lesson.
ultimatepython/engineering/benchmark.py	Adds engineering benchmarking/cProfile lesson.
ultimatepython/engineering/init.py	Introduces engineering package marker/docstring.
ultimatepython/concurrency/thread.py	Adds concurrency ThreadPoolExecutor lesson.
ultimatepython/concurrency/async.py	Adds concurrency asyncio lesson.
ultimatepython/concurrency/subinterpreters.py	Adds concurrency subinterpreters lesson.
ultimatepython/concurrency/init.py	Introduces concurrency package marker/docstring.
ultimatepython/advanced/walrus_operator.py	Adds advanced walrus-operator lesson.
ultimatepython/advanced/arg_enforcement.py	Adds advanced positional-only/keyword-only args lesson.
ultimatepython/advanced/template_strings.py	Adds advanced Python 3.14 t-strings lesson.
ui/src/i18n/ui.ts	Updates category i18n labels for new taxonomy.
ui/src/components/Sidebar.astro	Updates sidebar category ordering for new taxonomy.
ui/parse_lessons.py	Updates lesson parsing/category map/order for new structure.
README.md	Updates English curriculum outline to new structure.
README.de.md	Updates German curriculum outline to new structure.
README.es.md	Updates Spanish curriculum outline to new structure.
README.fr.md	Updates French curriculum outline to new structure.
README.hi.md	Updates Hindi curriculum outline to new structure.
README.ko.md	Updates Korean curriculum outline to new structure.
README.pt_br.md	Updates Brazilian Portuguese curriculum outline to new structure.
README.zh_tw.md	Updates Traditional Chinese curriculum outline to new structure.

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