[Tenuka22]

Summary of Changes

The documentation was half-backed and the website was missing the things a reader actually comes for. This PR brings both up to the engine's actual state, and adds the missing pages, the changelog, and the AI-facing surfaces.

New documentation pages (5) — each written from the implementation, not from the old prose:

Page	What it covers
/docs/strings	The bounded str[N] model: layout, the three methods (find, count, split), printing, pointers, and what strings cannot do
/docs/match	The enum dispatch statement: the four arm forms, the exhaustiveness rule, binding rules, the subject rules, and every refused shape
/docs/exceptions	try/except/else/finally over the closed set of seven engine traps, nesting, and the trap boundary
/docs/networking	A real TCP loopback from raw syscalls, checked against a C oracle, and the byte-order obligation
/docs/python-divergences	The eleven places Lithon deliberately differs from CPython, each with the reason

New site sections (2)

• /changelog — every shipped change, grouped by area, each entry linking to the documentation that covers it and to the commit.
• /next — the open items, item by item: the language gaps, the engine work, the toolchain debt, and the recently shipped list.

Docs index, rebuilt

• An explicit reading path: the 20 pages marked essential, in order, each stating the outcome you get from it.
• Every page carries a priority, so a reference lookup is never mistaken for reading material.
• Six new block kinds — callout, tabs, comparison, deflist, layout, quote — so the same concept can be shown several ways side by side.

Facts corrected against the implementation

• float[32] does not exist. It was advertised in the start page and the roadmap language page; it is now correctly documented as rejected (LITHON-E0105).
• A syscall argument may be a pointer, and it is a real host address in both tiers. The docs claimed pointers were rejected at compile time; the shipped TCP loopback depends on the opposite.
• len(xs) is the live length carried in a companion slot, not the capacity.
• **, //, <= and >= are refused outright, not "limited" or "not yet implemented".
• 55 IR opcodes, all emitted — not "26 of 27, Phi unemitted". The direct-Phi path ships.
• The benchmark and suite numbers now match benchmarks/results/latest.json (168.0×, 33/33 CTest, 46/46 typed, 18,379 encoder cases).
• The trap text is error: division by zero, not a LITHON-E code.
• The stale NotImplementedError: prefixes in the documented diagnostics are now the real LITHON-Ennnn: messages.

Encoding

314 runs of Windows-1252 mojibake repaired across the site, some of them double-encoded — including a stray , that rendered as , · not started on the roadmap. scripts/fix-encoding.ts is now a permanent guard, and it runs to zero.

AI-friendly

• llms.txt and llms-full.txt (144 KB of plain text), generated from the same registry the site renders.
• JSON-LD on every route, not just the docs pages.
• Body-text search, so an error code (E0301) or an operator (wrap_add) is findable — the palette previously suggested queries the engine could not answer.
• <lastmod> in the sitemap.

Also

• The "a small Lithon program" example now opens on its Execution tab rather than Source.
• The browser IR model no longer silently treats an unknown opcode as a no-op, and float registers and slots are scoped per frame (recursion no longer leaks float-ness).
• The playground falls back to the recorded IR in production instead of failing, and its SEO no longer advertises a live compiler that only exists in vite dev.
• The CI status footer caches for five minutes and only tracks master — the unauthenticated GitHub API allows 60 requests/hour/IP, and the footer was on every page.
• CI now runs verify-docs, the IR freshness check, typecheck and lint.
• The toolchain scripts work on every platform; the uv path was hard-coded to a Windows winget install.

Compiler Component Impacted

• Frontend / AST
• IR Generation
• Tier1 / JIT Execution Engine (tier_runner)
• x64 Codegen
• CI/CD & Benchmarks

No compiler, engine, or IR change. This PR is the website and the documentation only; the engine is untouched.

Verification

docs verification: 34 pages · 135 examples · 114 compiled · 67 repo refs
ALL DOCS EXAMPLES VERIFIED against the real Lithon toolchain

Every example on the site is compiled by the real Lithon frontend and pinned to the repo's regression outputs. bun run verify:docs runs the real tools/typecheck.py and src/frontend/frontend.py over every example and fails on drift — and CI now runs it, so a doc that drifts from the engine fails the build rather than misleading a reader.

Also green: typecheck, lint, build (47 routes prerendered), and the encoding guard.

Benchmark Verification

• Benchmarks executed locally (./benchmark_fib).
• Mamba bot verification expected on merge.

No benchmark numbers changed; the site now quotes benchmarks/results/latest.json accurately instead of a stale copy.