docs: automated documentation pipeline (per-symbol source → pages)

Replace the hardcoded landing page and minimal reference with a generated
documentation site driven by a single source of truth.

- docs/language/**: one file per symbol (93 keywords/types/builtins/namespace
  methods/operators/annotations), each with front-matter (id, kind, tokens,
  sig, tip) + description + a ```ludic example. Seeded by exploding the former
  inline SECTIONS list; these files are now the source of truth.
- docs/site/: site.json (editable hero/features/showcase/messaging, not
  hardcoded) + snippets/*.ludic (real programs shown on the landing page).
- tools/docgen/gen.py: generates index.html, api.html, ludic-highlight.js and
  symbols.json. The highlighter's symbol tables, hover tips and jump anchors
  are GENERATED from the per-symbol files — add a symbol and it is recognized,
  tipped and linked in every snippet automatically. Python stdlib only.
- tools/docgen/check.py: verifies the pages contract + that no snippet token
  links to a missing reference anchor.
- .forgejo/workflows/docs.yml: rebuilds and publishes to the pages branch on
  every push to main touching the docs sources.

Consumes the new Screen.*/Color.*/named-arg API and the 221-color palette.

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

docs/language/control/_section.md

@@ -0,0 +1,7 @@
+---
+id: control
+title: Control flow
+order: 2
+---
+
+Branches, loops, and state machines.

docs/language/control/kw-become.md

@@ -0,0 +1,12 @@
+---
+id: kw-become
+name: become
+category: control
+kind: keyword
+tokens: become
+sig: become Name
+tip: Transition: to another state of the enclosing machine, or to another scene.
+order: 8
+---
+
+Transition: to another <code>state</code> of the enclosing machine, or to another <code>scene</code>.

docs/language/control/kw-for.md

@@ -0,0 +1,16 @@
+---
+id: kw-for
+name: for … in
+category: control
+kind: keyword
+tokens: for
+sig: for name in a .. b { … }
+tip: Range loop.
+order: 2
+---
+
+Range loop. <b>Each pass binds a fresh, immutable <code>name</code></b> — it is not a variable you reuse or reassign; the range <code>a .. b</code> runs from <code>a</code> up to but not including <code>b</code>.
+
+```ludic
+for gy in 0 .. GRID_H { … }
+```

docs/language/control/kw-if.md

@@ -0,0 +1,12 @@
+---
+id: kw-if
+name: if / else
+category: control
+kind: keyword
+tokens: if else
+sig: if cond { … } else { … }
+tip: A branch.
+order: 0
+---
+
+A branch. Conditions are plain expressions; no parentheses required.

docs/language/control/kw-in.md

@@ -0,0 +1,12 @@
+---
+id: kw-in
+name: in
+category: control
+kind: keyword
+tokens: in
+sig: for x in range | query
+tip: Binds the loop name to each value of a range or query.
+order: 3
+---
+
+Binds the loop name to each value of a range or query.

docs/language/control/kw-machine.md

@@ -0,0 +1,16 @@
+---
+id: kw-machine
+name: machine
+category: control
+kind: keyword
+tokens: machine
+sig: machine store { state Name { … } }
+tip: A state machine over an int var (or register).
+order: 6
+---
+
+A state machine over an int <code>var</code> (or register). It dispatches on the store's value.
+
+```ludic
+machine turn_phase { state KnightMenu { … } }
+```

docs/language/control/kw-match.md

@@ -0,0 +1,12 @@
+---
+id: kw-match
+name: match / when
+category: control
+kind: keyword
+tokens: match
+sig: match x { when a, b => … }
+tip: Multi-way branch on a value, matching one or more literals per arm.
+order: 4
+---
+
+Multi-way branch on a value, matching one or more literals per arm.

docs/language/control/kw-state.md

@@ -0,0 +1,12 @@
+---
+id: kw-state
+name: state
+category: control
+kind: keyword
+tokens: state
+sig: state Name { … }
+tip: One state of a machine.
+order: 7
+---
+
+One state of a <code>machine</code>.

docs/language/control/kw-when.md

@@ -0,0 +1,12 @@
+---
+id: kw-when
+name: when
+category: control
+kind: keyword
+tokens: when
+sig: when value => result
+tip: One arm of a match.
+order: 5
+---
+
+One arm of a <code>match</code>.

docs/language/control/kw-while.md

@@ -0,0 +1,12 @@
+---
+id: kw-while
+name: while
+category: control
+kind: keyword
+tokens: while
+sig: while cond { … }
+tip: Loop while the condition holds.
+order: 1
+---
+
+Loop while the condition holds.