feat(debugger): integrate NX Tcl Remote Debugger into NX Postprocessor

Embed the NX Tcl Remote Debugger into the NX Postprocessor extension.
Add a new debugging client, protocol, and adapter logic to
drive attach/launch, breakpoints, stepping, and evaluation
via the runtime adapter.

- Introduced a client debugger with a new adapter and protocol
- Wired attach/launch, breakpoints, stepping, and evaluation
- Updated docs and licensing to reflect the embedded debugger

test/debugger.test.js

@@ -0,0 +1,63 @@
+"use strict"
+
+const test = require("node:test")
+const assert = require("node:assert/strict")
+const { PassThrough } = require("node:stream")
+const { NxDebugAdapter } = require("../client/src/debugger/debugAdapter")
+const manifest = require("../package.json")
+
+function dapMessage(message) {
+    const json = JSON.stringify(message)
+    return `Content-Length: ${Buffer.byteLength(json, "utf8")}\r\n\r\n${json}`
+}
+
+function readDapMessage(stream) {
+    return new Promise((resolve, reject) => {
+        let buffer = Buffer.alloc(0)
+        const timer = setTimeout(() => reject(new Error("DAP response timed out")), 2000)
+        const onData = (chunk) => {
+            buffer = Buffer.concat([buffer, chunk])
+            const headerEnd = buffer.indexOf("\r\n\r\n")
+            if (headerEnd < 0) return
+            const header = buffer.subarray(0, headerEnd).toString("ascii")
+            const match = /Content-Length:\s*(\d+)/i.exec(header)
+            if (!match) return
+            const length = Number(match[1])
+            if (buffer.length < headerEnd + 4 + length) return
+            clearTimeout(timer)
+            stream.removeListener("data", onData)
+            resolve(JSON.parse(buffer.subarray(headerEnd + 4, headerEnd + 4 + length)))
+        }
+        stream.on("data", onData)
+    })
+}
+
+test("integrated manifest contributes the NX Tcl debugger", () => {
+    const debuggerContribution = manifest.contributes.debuggers.find(
+        (entry) => entry.type === "nx-tcl"
+    )
+    assert.ok(debuggerContribution)
+    assert.deepEqual(debuggerContribution.languages, ["tcl", "def"])
+    assert.deepEqual(
+        manifest.contributes.breakpoints.map((entry) => entry.language),
+        ["tcl", "def"]
+    )
+})
+
+test("integrated adapter answers a DAP initialize request", async () => {
+    const input = new PassThrough()
+    const output = new PassThrough()
+    const adapter = new NxDebugAdapter(input, output)
+    const responsePromise = readDapMessage(output)
+
+    input.write(
+        dapMessage({ seq: 1, type: "request", command: "initialize", arguments: {} })
+    )
+    const response = await responsePromise
+    adapter.dispose()
+
+    assert.equal(response.success, true)
+    assert.equal(response.command, "initialize")
+    assert.equal(response.body.supportsConfigurationDoneRequest, true)
+    assert.equal(response.body.supportsSetVariable, true)
+})