docs(api): per-symbol pages, fuzzy search, deep token linking, hover cards

Rebuild the API Reference around one page per symbol and richer, verified content.

Pages & navigation
- One HTML page per symbol (kw-*, type-*, phase-*, screen-*, fn-*, annot-*, op-*)
  instead of a single scrolling page; namespace overview pages (ns-screen …
  ns-color) and a searchable index (api.html) with client-side fuzzy search.
- Sticky-header scroll offset (scroll-margin) so a jumped-to entry/param/color is
  never hidden, plus a flash highlight on the scrolled-to target.

Deep linking in every snippet & example
- Namespace members split: `Screen`→namespace page, `fill_rectangle`→method page;
  `Color`→palette page, `Charcoal`→its swatch — separately.
- Named arguments (`width:`) link to that parameter's anchor on the method page.
- Hover any token for a summary card built from the real API data (symbols.json).

Content & coverage
- Full authoritative surface documented from the compiler: every keyword, type,
  the 6 phases (Start/Input/FixedUpdate/Update/LateUpdate/Render, each its own
  page), all 22 annotations, namespace methods with parameter docs, builtins,
  the world_* reflection ABI, networking, operators — 155 symbols.
- Longer, clearer explanations; "model"/"model instance" terminology, not "entity";
  descriptive identifiers in every example (Position{column,row}, Velocity{delta_x,
  delta_y}, Health{current,maximum}, Player/Enemy) — no Pos/Seg/x/dx.
- Accuracy fixes from compiler ground-truth: world_count() takes no arg,
  world_query_next(property, cursor) arg order, event fields bind by name; dropped
  `when` and `module` (not in the self-hosted parser).

Tooling
- inventory.json + check.py: coverage guard (every symbol has a page), duplicate-
  token guard, and broken-link guard — fail CI so docs can't drift.
- validate.py: compiles every ```ludic example against bin/ludicc (158 compile).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tools/docgen/README.md

@@ -7,61 +7,81 @@ source of truth, so the site can never drift from the language.
 
 ```
 docs/
-  language/<category>/<id>.md    one file per symbol — keyword, type, builtin,
-                                 namespace method, operator, annotation
+  language/<category>/<id>.md    one file per symbol — keyword, type, phase,
+                                 builtin, namespace method, operator, annotation
   language/<category>/_section.md   section title + blurb + order
   language/colors/palette.json   the 221 named colors (generated by palette.py)
   site/site.json                 landing-page messaging (hero, features, …)
   site/snippets/*.ludic          the code shown on the landing page (real programs)
+tools/docgen/inventory.json      the authoritative symbol set the coverage guard checks
 ```
 
 ### A symbol file
 
 ```markdown
 ---
-id: kw-handler            # anchor in api.html (kw-*, type-*, fn-*, <ns>-*, op-*, annot-*)
-name: handler             # display name / heading
-category: control         # which section (matches the directory)
-kind: keyword             # keyword | type | phase | namespace-method | builtin | annotation | operator
-tokens: handler           # the literal token(s) the highlighter recognizes & links
-sig: handler Name phase P { … }
-tip: A block that runs each frame in a given phase.   # one-line hover tip
-order: 3
+id: screen-fill_rectangle     # anchor + page name (screen-fill_rectangle.html)
+name: Screen.fill_rectangle
+category: screen
+kind: namespace-method        # keyword|type|phase|namespace-method|builtin|annotation|operator
+tokens: Screen.fill_rectangle # literal token(s) the highlighter matches & links
+sig: Screen.fill_rectangle(x, y, width, height, color)
+tip: Draw a solid, filled rectangle.     # one sentence — the hover-card summary
+order: 1
+ns: Screen                    # namespace-method only
+member: fill_rectangle        # namespace-method only
+related: screen-clear screen-draw_rectangle
 ---
 
-Full description — inline HTML (`<code>`, `<b>`) and `backtick code` both work.
+Rich description — inline `<code>`/`backticks`, "model instance" language.
 
-```ludic
-handler Move phase Update { … }
-```
+Parameters:                   # for anything that takes arguments
+- `x` — the left edge, in pixels
+- `color` — the fill color, e.g. a `Color.*` name
+
+​```ludic
+program Example { … descriptive-named, compilable … }
+​```
 ```
 
-Add such a file and it appears in the API Reference, is recognized + tipped +
-linked in **every** code snippet across the site, and lands in `symbols.json` —
-with no other file to edit.
+## What it produces
 
-## Build
+One **page per symbol** (`<id>.html`), a namespace overview page per namespace
+(`ns-screen.html` … `ns-color.html`), a searchable **index** (`api.html`, fuzzy
+search over every symbol), the **landing page** (`index.html`), the
+`ludic-highlight.js` highlighter (all its symbol tables, tips, per-item link
+targets, per-parameter anchors and hover-card data generated from the sources
+above), `symbols.json`, and `.nojekyll`.
+
+In any code sample: keywords/types/builtins/annotations link to their page;
+`Screen.fill_rectangle` links `Screen` → the namespace page and `fill_rectangle`
+→ the method page separately; a named argument like `width:` links to that
+parameter's anchor; `Color.Charcoal` links `Color` and `Charcoal` separately;
+hovering any token shows a summary card from the real API data.
+
+## Build & check
 
 ```bash
-python3 tools/docgen/gen.py --out build/pages   # generate the whole site
-python3 tools/docgen/check.py build/pages        # sanity-check before publish
+python3 tools/docgen/gen.py --out build/pages    # generate the whole site
+python3 tools/docgen/check.py build/pages         # coverage + duplicate-token + link guard
+python3 tools/docgen/validate.py                  # compile every ```ludic example with bin/ludicc
 ```
 
-Outputs into `--out`: `index.html`, `api.html`, `ludic-highlight.js`
-(its symbol tables generated from the sources above), `symbols.json`, `.nojekyll`.
+`check.py` fails CI if any symbol in `inventory.json` lacks a page, if a token is
+documented on two pages, or if a highlighter link points at a missing page — so
+"every symbol is documented, autogenerated each time" is enforced. `validate.py`
+needs a built `bin/ludicc`; the deploy CI is Python-only, so run it locally or in
+a toolchain-enabled job.
 
 No third-party dependencies — Python standard library only.
 
 ## Publish
 
-`.forgejo/workflows/docs.yml` runs this on every push to `main` that touches
-`docs/**` or `tools/docgen/**`, and force-publishes the result to the `pages`
-branch root (which the pages-server serves). It needs a repo secret
-`PAGES_TOKEN` with write access (or the automatic Actions token enabled for
-pushes). `index.html` + `.nojekyll` always stay at the branch root.
+`.forgejo/workflows/docs.yml` runs `gen.py` + `check.py` on every push to `main`
+that touches `docs/**` or `tools/docgen/**`, and publishes the result to the
+`pages` branch root. `index.html` + `.nojekyll` always stay at the root.
 
 ## Colors
 
 `palette.json` is generated by `tools/docgen/palette.py` from a single `PALETTE`
-table, which also generates `selfhost/emit_color.ludic`. Regenerate colors
-there; never hand-edit either output.
+table, which also generates `selfhost/emit_color.ludic`. Regenerate colors there.