Claude/windows install compatibility tr di s (#3)

* Fix Windows PowerShell 5.1 compatibility in installer

Use $env:PROCESSOR_ARCHITECTURE for arch detection instead of
RuntimeInformation::OSArchitecture which may not be loaded in
every Windows PowerShell 5.1 session. Also fix null-reference
when user PATH environment variable is empty.

https://claude.ai/code/session_01VFiRDM2ZweyacXN5JneVoP

* Fix executable resolution and tar extraction on Windows

resolveExecutable() used `sh -lc "command -v ..."` which doesn't work
on Windows (no sh). Now uses `cmd /c where` on win32. Also make tar
workspace restoration tolerate symlink failures on Windows — .bin/
symlinks can't be created without Developer Mode, but the actual
package directories are extracted fine.

https://claude.ai/code/session_01VFiRDM2ZweyacXN5JneVoP

* Broad Windows compatibility fixes across the codebase

- runtime.ts: Use path.delimiter instead of hardcoded ":" for PATH
  construction — was completely broken on Windows
- executables.ts: Add Windows fallback paths for Chrome, Edge, Brave,
  and Pandoc in Program Files; skip macOS-only paths on win32
- node-version.ts, check-node-version.mjs, bin/feynman.js: Show
  Windows-appropriate install instructions (irm | iex, nodejs.org)
  instead of nvm/curl on win32
- preview.ts: Support winget for pandoc auto-install on Windows, and
  apt on Linux (was macOS/brew only)
- launch.ts: Catch unsupported signal errors on Windows
- README.md: Add Windows PowerShell commands alongside macOS/Linux
  for all install instructions

https://claude.ai/code/session_01VFiRDM2ZweyacXN5JneVoP

* fix: complete windows bootstrap hardening

---------

Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: Advait Paliwal <advaitspaliwal@gmail.com>

src/system/executables.ts

@@ -1,27 +1,36 @@
 import { spawnSync } from "node:child_process";
 import { existsSync } from "node:fs";
 
-export const PANDOC_FALLBACK_PATHS = [
-	"/opt/homebrew/bin/pandoc",
-	"/usr/local/bin/pandoc",
-];
+const isWindows = process.platform === "win32";
+const programFiles = process.env.PROGRAMFILES ?? "C:\\Program Files";
+const localAppData = process.env.LOCALAPPDATA ?? "";
 
-export const BREW_FALLBACK_PATHS = [
-	"/opt/homebrew/bin/brew",
-	"/usr/local/bin/brew",
-];
+export const PANDOC_FALLBACK_PATHS = isWindows
+	? [`${programFiles}\\Pandoc\\pandoc.exe`]
+	: ["/opt/homebrew/bin/pandoc", "/usr/local/bin/pandoc"];
 
-export const BROWSER_FALLBACK_PATHS = [
-	"/Applications/Google Chrome.app/Contents/MacOS/Google Chrome",
-	"/Applications/Chromium.app/Contents/MacOS/Chromium",
-	"/Applications/Brave Browser.app/Contents/MacOS/Brave Browser",
-	"/Applications/Microsoft Edge.app/Contents/MacOS/Microsoft Edge",
-];
+export const BREW_FALLBACK_PATHS = isWindows
+	? []
+	: ["/opt/homebrew/bin/brew", "/usr/local/bin/brew"];
 
-export const MERMAID_FALLBACK_PATHS = [
-	"/opt/homebrew/bin/mmdc",
-	"/usr/local/bin/mmdc",
-];
+export const BROWSER_FALLBACK_PATHS = isWindows
+	? [
+			`${programFiles}\\Google\\Chrome\\Application\\chrome.exe`,
+			`${programFiles} (x86)\\Google\\Chrome\\Application\\chrome.exe`,
+			`${localAppData}\\Google\\Chrome\\Application\\chrome.exe`,
+			`${programFiles}\\Microsoft\\Edge\\Application\\msedge.exe`,
+			`${programFiles}\\BraveSoftware\\Brave-Browser\\Application\\brave.exe`,
+		]
+	: [
+			"/Applications/Google Chrome.app/Contents/MacOS/Google Chrome",
+			"/Applications/Chromium.app/Contents/MacOS/Chromium",
+			"/Applications/Brave Browser.app/Contents/MacOS/Brave Browser",
+			"/Applications/Microsoft Edge.app/Contents/MacOS/Microsoft Edge",
+		];
+
+export const MERMAID_FALLBACK_PATHS = isWindows
+	? []
+	: ["/opt/homebrew/bin/mmdc", "/usr/local/bin/mmdc"];
 
 export function resolveExecutable(name: string, fallbackPaths: string[] = []): string | undefined {
 	for (const candidate of fallbackPaths) {
@@ -30,13 +39,19 @@ export function resolveExecutable(name: string, fallbackPaths: string[] = []): s
 		}
 	}
 
-	const result = spawnSync("sh", ["-lc", `command -v ${name}`], {
-		encoding: "utf8",
-		stdio: ["ignore", "pipe", "ignore"],
-	});
+	const isWindows = process.platform === "win32";
+	const result = isWindows
+		? spawnSync("cmd", ["/c", `where ${name}`], {
+				encoding: "utf8",
+				stdio: ["ignore", "pipe", "ignore"],
+			})
+		: spawnSync("sh", ["-lc", `command -v ${name}`], {
+				encoding: "utf8",
+				stdio: ["ignore", "pipe", "ignore"],
+			});
 
 	if (result.status === 0) {
-		const resolved = result.stdout.trim();
+		const resolved = result.stdout.trim().split(/\r?\n/)[0];
 		if (resolved) {
 			return resolved;
 		}

src/system/node-version.ts

@@ -26,10 +26,15 @@ export function isSupportedNodeVersion(version = process.versions.node): boolean
 }
 
 export function getUnsupportedNodeVersionLines(version = process.versions.node): string[] {
+	const isWindows = process.platform === "win32";
 	return [
 		`feynman requires Node.js ${MIN_NODE_VERSION} or later (detected ${version}).`,
-		"Switch to Node 20 with `nvm install 20 && nvm use 20`, or use the standalone installer:",
-		"curl -fsSL https://feynman.is/install | bash",
+		isWindows
+			? "Install a newer Node.js from https://nodejs.org, or use the standalone installer:"
+			: "Switch to Node 20 with `nvm install 20 && nvm use 20`, or use the standalone installer:",
+		isWindows
+			? "irm https://feynman.is/install.ps1 | iex"
+			: "curl -fsSL https://feynman.is/install | bash",
 	];
 }