refactor(mcp-server): remove dead code and fold repeated tool plumbing

- index.ts: registerTool() does the session check, try/catch and the
  write queue for all 15 tools; fail()/ok(), syncFromBrowser(),
  commitDocument() and describePages() replace the copied blocks; drop
  pickPageSelector, currentSession.version, the input ?? {} defaults;
  add_page reuses prepareNewModel() split out of prepareNewDiagram
- xml-validation.ts: drop the hand-written syntax checks that saxes
  already reports, MAX_XML_SIZE and the stale header
- http-server.ts: one pendingExport object, no unread response fields,
  no CORS/OPTIONS branch for same-origin requests, fewer exports
- diagram-operations parseNewCell(), addHistory returns void,
  normalizeToMxfile without host, foldCells without layer, expandStyles
  removed, unused preview.css rule removed, no .d.ts output
- xml-examples.ts styleRules() shares the Styles paragraphs with the
  web prompt
- tests: setupFiles installs the DOM polyfill once, server-wiring uses
  the SDK client, mcp-core.test.ts drops the cases MCP tests already
  cover

tests/unit/compact-cells.test.ts

@@ -299,8 +299,9 @@ describe("review round: cells the model may write", () => {
         expect(outcome.xml).toContain(
             '<mxCell id="3" value="B" vertex="1" parent="L1"',
         )
-        expect(foldCells(file, "L1")).toContain(
-            '<mxCell id="2" value="Start" style="rounded=1;" x="40" y="40" w="120" h="60"/>',
+        // Folding keeps a parent other than the default layer "1"
+        expect(foldCells(file)).toContain(
+            '<mxCell id="2" value="Start" style="rounded=1;" parent="L1" x="40" y="40" w="120" h="60"/>',
         )
     })
 

tests/unit/mcp-core.test.ts

@@ -14,11 +14,7 @@ import {
     wrapCellsInModel,
 } from "@/packages/mcp-server/src/pages.ts"
 import { getXmlSyntaxError } from "@/packages/mcp-server/src/xml-syntax.ts"
-import {
-    autoFixXml,
-    validateAndFixXml,
-    validateMxCellStructure,
-} from "@/packages/mcp-server/src/xml-validation.ts"
+import { validateAndFixXml } from "@/packages/mcp-server/src/xml-validation.ts"
 
 const box = (id: string, parent = "1") =>
     `<mxCell id="${id}" value="${id}" vertex="1" parent="${parent}"><mxGeometry x="0" y="0" width="80" height="40" as="geometry"/></mxCell>`
@@ -93,177 +89,6 @@ describe("MCP diagram modules with a browser DOM", () => {
     })
 })
 
-// Repair cases fixed in the web app's own copy before it moved here
-const page = (id: string, cells: string) =>
-    `<diagram name="${id}" id="${id}"><mxGraphModel><root><mxCell id="0"/><mxCell id="1" parent="0"/>${cells}</root></mxGraphModel></diagram>`
-
-describe("duplicate ids in multi-page documents", () => {
-    const shape = (id: string, value = "Box") =>
-        `<mxCell id="${id}" value="${value}" vertex="1" parent="1"><mxGeometry x="0" y="0" width="80" height="40" as="geometry"/></mxCell>`
-
-    it("accepts the same ids on different pages", () => {
-        const xml = `<mxfile>${page("p1", shape("2"))}${page("p2", shape("2"))}</mxfile>`
-        expect(validateMxCellStructure(xml)).toBeNull()
-    })
-
-    it("still reports duplicate ids within one page", () => {
-        const xml = `<mxfile>${page("p1", shape("2") + shape("2"))}${page("p2", "")}</mxfile>`
-        expect(validateMxCellStructure(xml)).toMatch(/duplicate cell ID/i)
-    })
-
-    it("does not rename the root cells of other pages when fixing", () => {
-        const xml = `<mxfile>${page("p1", shape("2", "R&D"))}${page("p2", shape("3"))}</mxfile>`
-        const result = validateAndFixXml(xml)
-        expect(result.valid).toBe(true)
-        expect(result.fixed).not.toContain("_dup")
-        expect(result.fixed).toContain("R&amp;D")
-    })
-
-    it("renames a duplicate id in a bare model, as display_diagram has", () => {
-        // In an <mxfile> the duplicate is reported instead (above)
-        const xml = `<mxGraphModel><root><mxCell id="0"/><mxCell id="1" parent="0"/>${shape("d") + shape("d")}</root></mxGraphModel>`
-        const { fixed } = autoFixXml(xml)
-        expect(fixed).toContain('<mxCell id="d" ')
-        expect(fixed).toContain('<mxCell id="d_dup1" ')
-    })
-})
-
-describe("autoFixXml", () => {
-    it("does not insert a space at the start of style values", () => {
-        const xml = `<mxGraphModel><root><mxCell id="0"/><mxCell id="1" parent="0"/><mxCell id="2" value="R&D" style="rounded=1;whiteSpace=wrap;" vertex="1" parent="1"><mxGeometry as="geometry"/></mxCell></root></mxGraphModel>`
-        const { fixed } = autoFixXml(xml)
-        expect(fixed).toContain('style="rounded=1;whiteSpace=wrap;"')
-    })
-
-    it("adds a missing space between attributes", () => {
-        const xml = `<mxCell id="2" vertex="1"parent="1"/>`
-        expect(autoFixXml(xml).fixed).toContain('vertex="1" parent="1"')
-    })
-
-    it("keeps &quot; inside rich text labels", () => {
-        const label = "&lt;font color=&quot;#ff0000&quot;&gt;Hello&lt;/font&gt;"
-        const xml = `<mxGraphModel><root><mxCell id="0"/><mxCell id="1" parent="0"/><mxCell id="2" value="${label}" style="html=1;" vertex="1" parent="1"><mxGeometry as="geometry"/></mxCell><mxCell id="3" value="Q&A" vertex="1" parent="1"><mxGeometry as="geometry"/></mxCell></root></mxGraphModel>`
-        const result = validateAndFixXml(xml)
-        expect(result.valid).toBe(true)
-        expect(result.fixed).toContain(`value="${label}"`)
-    })
-
-    it("fixes an attribute delimited by &quot;", () => {
-        const xml = `<mxCell id="2" dashPattern=&quot;1 1;&quot; vertex="1" parent="1"/>`
-        expect(autoFixXml(xml).fixed).toContain('dashPattern="1 1;"')
-    })
-
-    it("keeps cells written on one line next to multi-line cells", () => {
-        const xml = `<mxGraphModel><root>
-<mxCell id="0"/>
-<mxCell id="1" parent="0"/>
-<mxCell id="2" value="Q&A" vertex="1" parent="1">
-  <mxGeometry x="0" y="0" width="80" height="40" as="geometry"/>
-</mxCell>
-<mxCell id="e1" edge="1" parent="1" source="2" target="3"><mxGeometry relative="1" as="geometry"/></mxCell>
-<mxCell id="3" value="B" vertex="1" parent="1">
-  <mxGeometry x="200" y="0" width="80" height="40" as="geometry"/>
-</mxCell>
-</root></mxGraphModel>`
-        const result = validateAndFixXml(xml)
-        expect(result.valid).toBe(true)
-        for (const id of ["2", "e1", "3"]) {
-            expect(result.fixed).toContain(`<mxCell id="${id}"`)
-        }
-    })
-
-    it("keeps object and UserObject wrappers", () => {
-        const xml = `<mxGraphModel><root><mxCell id="0"/><mxCell id="1" parent="0"/><UserObject id="2" label="Docs" link="https://example.com"><mxCell vertex="1" parent="1"><mxGeometry as="geometry"/></mxCell></UserObject><object id="3" label="A&B" owner="me"><mxCell vertex="1" parent="1"><mxGeometry as="geometry"/></mxCell></object></root></mxGraphModel>`
-        const result = validateAndFixXml(xml)
-        expect(result.valid).toBe(true)
-        expect(result.fixed).toContain('<UserObject id="2"')
-        expect(result.fixed).toContain('<object id="3"')
-    })
-})
-
-describe("hasCells (was isMinimalDiagram in the web app)", () => {
-    it("returns true for empty diagram", () => {
-        const xml = '<mxCell id="0"/><mxCell id="1" parent="0"/>'
-        expect(hasCells(xml)).toBe(false)
-    })
-
-    it("returns false for diagram with content", () => {
-        const xml =
-            '<mxCell id="0"/><mxCell id="1" parent="0"/><mxCell id="2" value="Hello"/>'
-        expect(hasCells(xml)).toBe(true)
-    })
-
-    it("handles whitespace correctly", () => {
-        const xml = '  <mxCell id="0"/>  <mxCell id="1" parent="0"/>  '
-        expect(hasCells(xml)).toBe(false)
-    })
-
-    it("returns false for a shape drawn in draw.io with a random id", () => {
-        const xml =
-            '<mxGraphModel><root><mxCell id="0"/><mxCell id="1" parent="0"/><mxCell id="xY3kQ9-1" value="" style="rounded=0;" vertex="1" parent="1"><mxGeometry x="10" y="10" width="120" height="60" as="geometry"/></mxCell></root></mxGraphModel>'
-        expect(hasCells(xml)).toBe(true)
-    })
-
-    it("does not mistake ids that start with 0 or 1 for root cells", () => {
-        const xml =
-            '<mxCell id="0"/><mxCell id="1" parent="0"/><mxCell id="10"/>'
-        expect(hasCells(xml)).toBe(true)
-    })
-
-    it("counts a cell wrapped in a UserObject", () => {
-        const xml =
-            '<mxCell id="0"/><mxCell id="1" parent="0"/><UserObject id="u" link="x"><mxCell vertex="1" parent="1"/></UserObject>'
-        expect(hasCells(xml)).toBe(true)
-    })
-})
-
-describe("applyDiagramOperations with wrapped cells", () => {
-    const xml = `<mxfile><diagram id="p1"><mxGraphModel><root><mxCell id="0"/><mxCell id="1" parent="0"/><UserObject id="5" label="Docs" link="https://example.com"><mxCell vertex="1" parent="1"><mxGeometry as="geometry"/></mxCell></UserObject><mxCell id="6" value="B" vertex="1" parent="1"><mxGeometry as="geometry"/></mxCell><mxCell id="e1" edge="1" parent="1" source="5" target="6"><mxGeometry relative="1" as="geometry"/></mxCell></root></mxGraphModel></diagram></mxfile>`
-
-    it("deletes a wrapped cell and its edges", () => {
-        const { result, errors } = applyDiagramOperations(xml, [
-            { operation: "delete", cell_id: "5" },
-            { operation: "delete", cell_id: "e1" },
-        ])
-        expect(errors).toEqual([])
-        expect(result).not.toContain("UserObject")
-        expect(result).not.toContain('id="e1"')
-        expect(result).toContain('id="6"')
-    })
-
-    it("rejects adding a cell with the id of a wrapped cell", () => {
-        const { errors } = applyDiagramOperations(xml, [
-            {
-                operation: "add",
-                cell_id: "5",
-                new_xml: '<mxCell id="5" vertex="1" parent="1"/>',
-            },
-        ])
-        expect(errors[0]?.message).toContain("already exists")
-    })
-
-    it("updates a wrapped cell", () => {
-        const { result, errors } = applyDiagramOperations(xml, [
-            {
-                operation: "update",
-                cell_id: "5",
-                new_xml:
-                    '<UserObject id="5" label="New" link="https://example.org"><mxCell vertex="1" parent="1"><mxGeometry as="geometry"/></mxCell></UserObject>',
-            },
-        ])
-        expect(errors).toEqual([])
-        expect(result).toContain('label="New"')
-        expect(result).not.toContain('label="Docs"')
-    })
-
-    it("reports deleting a cell that does not exist", () => {
-        const { errors } = applyDiagramOperations(xml, [
-            { operation: "delete", cell_id: "missing" },
-        ])
-        expect(errors[0]?.message).toContain("not found")
-    })
-})
-
 describe("edit_diagram on one page of a multi-page file", () => {
     // Page A has an edge "g"; on page B, "g" is a shape on layer "L"
     const twoPages = `<mxfile><diagram id="pa" name="A"><mxGraphModel><root><mxCell id="0"/><mxCell id="1" parent="0"/>${box("s")}${box("t")}<mxCell id="g" edge="1" parent="1" source="s" target="t"><mxGeometry relative="1" as="geometry"/></mxCell></root></mxGraphModel></diagram><diagram id="pb" name="B"><mxGraphModel><root><mxCell id="0"/><mxCell id="L" parent="0"/>${box("g", "L")}</root></mxGraphModel></diagram></mxfile>`

tests/unit/mcp-preview-recovery.test.ts

@@ -445,7 +445,7 @@ describe("MCP preview History and a recreated session", () => {
     }
     const historyList = {
         status: 200,
-        body: { entries: [{ id: 5, index: 0, svg: "" }], count: 1 },
+        body: { entries: [{ id: 5, index: 0, svg: "" }] },
     }
     const modalOpen = () =>
         document.getElementById("history-modal")?.classList.contains("open")

tests/unit/style-classes.test.ts

@@ -9,10 +9,15 @@ import {
 import {
     addDefaultStyles,
     applyStyleClasses,
-    expandStyles,
     readStyleClasses,
 } from "@/packages/mcp-server/src/style-classes.ts"
 
+/** The named styles of a model's XML expanded, with the default styles */
+const expandStyles = (xml: string) => {
+    const { classes, xml: cells } = readStyleClasses(xml)
+    return addDefaultStyles(applyStyleClasses(cells, classes))
+}
+
 const geometry =
     '<mxGeometry x="0" y="0" width="80" height="40" as="geometry"/>'
 const cell = (id: string, style: string, extra = "") =>