feat(course): course 0 -- t27 basics in 27 modules with infographics

[gHashTag]

Closes #1464

Stacked on #1456 (base head 52a84af). Merge #1456 first; this branch then rebases onto main.

Course 0, t27-basics: 27 modules of one lesson on the t27 language, before the FPGA course and the AI numbers course. Each lesson opens one black-and-white infographic (a real <table> with caption and header cells, plus an SVG flow diagram with a <title> in some lessons; one card per row under 480px) and one lesson spec that compiles clean on all 7 backends in the site's wasm compiler with its tests passing.

• specs/course/t27-basics.t27, t27-basics-ru.t27, i18n/t27-basics.ru.json
• specs/course/courses.t27: three courses chained t27-basics -> course -> ai-numbers. The first course takes learn/ (generator rule), so course 1's index moves to learn/course/; lesson pages stay at learn/<lesson>/. Older blog links to course 1 now point at learn/course/.
• 27 widget specs specs/widgets/basics-*.t27 (words and rows in the spec), one shared public/widgets/infographic.js + .css (hand-written JS, no words of its own), B&W cards; gallery is 96 widgets
• scripts/course-pages.mjs: the learn/ landing lists the three courses, with a test
• routes #/t27-basics, starfield root, nav entry
• blog post course-zero-t27-basics with EN body and RU ruBody
• specs/catalog/onboarding.t27: llms.txt and agents.t27 name all three courses

course-27 checklist (~/.claude/skills/course-27/course-27.t27)

Steps: pick done (roadmap.t27 LIVE 3); specs PARTIAL, the 27 lesson specs are in the site mirror and not yet in gHashTag/t27; shape done; words done (no superlatives, generator check); russian done; widgets PARTIAL, 27 own B&W widgets with spec tests, but no casts; catalog done; generate done; preview NOT done in a browser; post done; land done here (issue, PR, report), merge left to a reviewer; ship, social pending after merge; learn done for roadmap.t27.

Rules: twenty-seven, spec-and-widget, black-and-white, post-per-pr, seo, no-superlatives, no-reddit, owner-says-yes hold. numbers-from-runs holds for the infographic data (wasm compiler runs). casts-through-tri is NOT met: the widgets are infographics, not tri recordings; the 27 casts are pending, as for the gft lessons, and none is faked.

Gates: all 8 rc 0 on a3c0d40 (check:widgets, test:widgets-spec, check:widget-pages, check:course, test:course, check:course-pages, check:onboarding, tsc).

Follow-up on e8519e1: Russian infographic words (contract specs/widgets/i18n/widgets-ru.t27 + bundle i18n/widgets.ru.json, swapped in by ?lang=ru), shared files in the ?v= stamp, stale play pages from #1456 regenerated, and check:subpath-urls fixed (Course.tsx:60). Gates rc 0 on e8519e1: check:widgets, test:widgets-spec, check:widget-pages, check:course, test:course, check:course-pages, check:onboarding, check:play, check:subpath-urls, tsc.

{
  "version": 1,
  "head_sha": "d907f2b5153590bbc49a90fc4ed02d04599b4633",
  "summary": "Course 0, t27 basics: 27 modules of one lesson on the t27 language, each with a black-and-white table or diagram drawn from its own widget spec and a lesson spec that compiles on all 7 backends.",
  "changes": [
    "apps/website/specs/course/t27-basics.t27 and t27-basics-ru.t27, i18n/t27-basics.ru.json: the course, its Russian contract and bundle",
    "apps/website/specs/course/courses.t27: three courses, t27-basics first; course.t27 share path moves to learn/course/",
    "apps/website/specs/widgets/basics-*.t27 and public/widgets/basics-*/: 27 infographic widgets with cards; gallery.t27 at 96",
    "apps/website/public/widgets/infographic.js and infographic.css: one shared renderer for table and SVG flow",
    "apps/website/public/t27/files/specs/basics/: 27 lesson specs",
    "apps/website/scripts/course-pages.mjs: the learn/ landing lists every course; course-from-spec test indices shifted by one course",
    "apps/website/src: routes, starfield, nav entry, blog post course-zero-t27-basics, generated catalogs and pages",
    "apps/website/scripts/widget-pages-from-spec.mjs: Russian SAY_ words from i18n/widgets.ru.json under the contract specs/widgets/i18n/widgets-ru.t27; the ?v= stamp hashes widget.css and shared files a widget loads, applied to shared modules by an import map"
  ],
  "tests": [
    {
      "command": "npm run check:course, check:course-pages, check:widgets, check:widget-pages",
      "result": "3 courses of 27 lessons, 96 widgets, 81 lesson specs compile clean, spec tests 21 with 101 asserts hold; 168 course pages and cards current",
      "status": "passed",
      "evidence": "local runs, rc 0 each"
    },
    {
      "command": "npm run test:course, test:widget-pages, test:widgets-spec; node --test scripts/course-pages.test.mjs and the two blog-cover tests",
      "result": "course 22 of 22, course-pages 9 of 9, blog cover tests 12 of 12, widget tests pass",
      "status": "passed",
      "evidence": "local node --test summaries"
    },
    {
      "command": "t27check on t27-basics.t27, t27-basics-ru.t27, courses.t27; tsc --noEmit",
      "result": "all clean; typecheck rc 0",
      "status": "passed",
      "evidence": "local runs on the branch head e8519e1d7"
    },
    {
      "command": "npm run check:onboarding",
      "result": "llms.txt and agents.t27 name the three courses; spec tests 10, asserts 55 hold",
      "status": "passed",
      "evidence": "local run on a3c0d408"
    },
    {
      "command": "lefthook pre-commit and commit-msg",
      "result": "language contracts pass, subject is English ASCII",
      "status": "passed",
      "evidence": "hook output on 127ac93fa"
    },
    {
      "command": "npm run check:play, check:subpath-urls; negative control: drop basics-trits.SAY_NOTE and shorten basics-arrays.SAY_TABLE_HEAD in the bundle",
      "result": "both gates rc 0; the control fails widget-pages-from-spec with 2 named problems, restoring the bundle makes it pass",
      "status": "passed",
      "evidence": "local runs on e8519e1d"
    }
  ],
  "limitations": [
    "The pages were not opened in a browser for this PR; the cards were checked as images",
    "The browser runner skips invariant and bench blocks, and does not load modules named by use",
    "The lesson specs live in the site mirror, not yet in gHashTag/t27",
    "No lesson has a tri cast yet; casts-through-tri is pending for all 27",
    "Russian widget words cover only the SAY_ fields of the basics-* widgets; other widgets and the widget page head and foot stay English (hidden inside course frames)"
  ],
  "tags": [
    "t27",
    "course",
    "infographics"
  ],
  "blog": {
    "title": "Course 0: t27 basics in 27 lessons, each with an infographic",
    "summary": "A new course comes before the FPGA and AI numbers courses: 27 lessons on the t27 language, each with a table or diagram drawn from its own spec.",
    "outline": [
      "The two existing t27 courses start at the chip and assume the reader already reads a spec, so a course on the language itself now comes before them.",
      "Each of the 27 lessons is its own module, from what a spec is and the module line through types, functions and tests to the compiler and its backends.",
      "Every lesson opens one black-and-white table or flow diagram whose words and rows live in a t27 widget spec with its own tests.",
      "Every lesson spec compiles clean on all seven backends in the browser, and the course generator refuses to build if one does not.",
      "The post names what is still missing: skipped invariant blocks in the browser, and specs not yet in the t27 repository."
    ]
  }
}

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