tools: add wiki-gen — regenerates topic-contract AUTOGEN blocks

Generates the markdown table inside <!-- BEGIN AUTOGEN: topic-contract -->
blocks in nodes/<n>/wiki/Reference-Contracts.md from the canonical registry
at src/commands/index.js. Replaces the agent-written placeholders the wiki
uplift left behind.

- Accepts both labelled and unlabelled END markers; rewrites to canonical
  '<!-- END AUTOGEN: topic-contract -->' on regeneration so future runs are
  consistent.
- --check mode for CI (exit 1 if any block is out of date).
- Out of scope for now: data-model AUTOGEN block (requires instantiating
  the domain; the 9 agent-written placeholders for that block stay until
  a follow-up tool lands).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tools/wiki-gen/README.md

@@ -0,0 +1,52 @@
+# @evolv/wiki-gen
+
+Generate the AUTOGEN sections of per-node wikis from the source of truth
+(`nodes/<n>/src/commands/index.js`).
+
+## What it generates
+
+Replaces content between these markers:
+
+```markdown
+<!-- BEGIN AUTOGEN: topic-contract — populate via wiki-gen tool (TODO) -->
+... wiki-gen overwrites this block ...
+<!-- END AUTOGEN: topic-contract -->
+```
+
+The 9 wikis uplifted in 2026-05 carry these markers in
+`wiki/Reference-Contracts.md` (and some in `wiki/Home.md`); `wiki-gen`
+keeps them in sync with the registry.
+
+## Usage
+
+```bash
+# regenerate every node
+node tools/wiki-gen/bin/wiki-gen.js
+
+# one node
+node tools/wiki-gen/bin/wiki-gen.js nodes/rotatingMachine
+
+# CI check: fail if any AUTOGEN block is out of date
+node tools/wiki-gen/bin/wiki-gen.js --check
+```
+
+## What it writes
+
+For each registry descriptor:
+
+| Column | Source |
+|---|---|
+| Canonical topic | `descriptor.topic` |
+| Aliases | `descriptor.aliases` (deprecation candidates) |
+| Payload | `descriptor.payloadSchema` |
+| Unit | `descriptor.units.measure` + `descriptor.units.default` (or `—`) |
+| Effect | `descriptor.description` |
+
+## Out of scope (for now)
+
+- The `data-model` AUTOGEN block (sample of `getOutput()`) — requires
+  instantiating the domain class, which depends on `generalFunctions`.
+  The 9 wikis carry hand-written placeholders inside those markers;
+  upgrading to runtime sampling is a follow-up.
+
+Run after touching `src/commands/index.js` in any node, or as a CI gate.