Documentation site and CI workflows

An mdBook under docs/book: a user guide (getting started, UI tour, sketching, features,
parameters, components and joints, sheet metal, plastic, files, shortcuts, MCP) and a developer
guide (CONTRIBUTING, architecture, command engine, kernel boundary, persistent naming, test
harnesses, and the existing docs/*.md pages). `cargo xtask book` generates the command reference
from `solvecraft-cli commands` and renders the screenshots with `solvecraft-cli snapshot`, then
runs mdbook. .github/workflows/pages.yml publishes the book at /solvecraft/ and the web app at
/solvecraft/app/ (skipped while the repository is private). .github/workflows/ci.yml runs
`cargo xtask ci` on pull requests. README and Help → Documentation link to the book.

Fixes #28
Fixes #8

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/book/scripts/enclosure.json

@@ -0,0 +1,7 @@
+{"commands": [
+  {"command": "solid.box", "params": {"length": 70, "width": 45, "height": 25, "body_name": "Enclosure"}},
+  {"command": "solid.fillet", "params": {"edges": [[0, 0, 12], [70, 0, 12], [70, 45, 12], [0, 45, 12]], "radius": 6}},
+  {"command": "solid.shell", "params": {"faces": [[35, 22, 25]], "thickness": 2}},
+  {"command": "plastic.boss", "params": {"position": [12, 12, 2], "diameter": 7, "height": 14, "hole_diameter": 2.5}},
+  {"command": "plastic.boss", "params": {"position": [58, 33, 2], "diameter": 7, "height": 14, "hole_diameter": 2.5}}
+]}

docs/book/scripts/revolve.json

@@ -0,0 +1,11 @@
+{"commands": [
+  {"command": "sketch.create", "params": {"plane": "XZ", "name": "Section"}},
+  {"command": "sketch.line", "params": {"points": [[6, 0], [30, 0], [30, 4], [12, 4], [12, 20], [6, 20]], "closed": true}},
+  {"command": "sketch.finish", "params": {}},
+  {"command": "solid.revolve", "params": {"axis": "Z", "body_name": "Hub"}},
+  {"command": "sketch.create", "params": {"plane": "XY", "name": "Bolt holes"}},
+  {"command": "sketch.circle.center", "params": {"center": [22, 0], "diameter": 5}},
+  {"command": "sketch.finish", "params": {}},
+  {"command": "solid.extrude", "params": {"distance": 4, "operation": "cut", "name": "Bolt hole"}},
+  {"command": "solid.pattern.circular", "params": {"features": ["Bolt hole"], "axis": "Z", "count": 6}}
+]}

docs/book/scripts/sheet-metal.json

@@ -0,0 +1,9 @@
+{"commands": [
+  {"command": "sheet.manage_rules", "params": {"name": "Steel 1.5", "thickness": "1.5 mm", "bend_radius": "1.5 mm", "k_factor": 0.44, "active": true}},
+  {"command": "sketch.create", "params": {"plane": "XY", "name": "Base"}},
+  {"command": "sketch.rectangle.two_point", "params": {"p0": [0, 0], "p1": [80, 50]}},
+  {"command": "sketch.finish", "params": {}},
+  {"command": "sheet.flange", "params": {"type": "base"}},
+  {"command": "sheet.flange", "params": {"edges": [[40, 0, 1.5]], "height": 20}},
+  {"command": "sheet.flange", "params": {"edges": [[40, 50, 1.5]], "height": 20}}
+]}