fix: validate sandbox plugin exports and fix plugin packaging (#363)

* fix(webhook-notifier): add build step and export built files

The webhook-notifier plugin exported raw TypeScript source from its
package.json exports (./sandbox pointed to src/sandbox-entry.ts).
When the Vite plugin resolved this at site build time, it embedded
unbuilt TypeScript into the sandbox module, causing "Unexpected token
'{'" errors at runtime.

Add a tsdown build step (matching sandboxed-test's pattern) and update
the exports map to point to dist/*.mjs.

Fixes #150

* fix(core): reject unbuilt source in sandbox module generator and bundle validator

Add two validation checks to prevent plugins with misconfigured exports
from silently breaking site builds:

1. generateSandboxedPluginsModule() now throws a clear error if a
   sandbox entrypoint resolves to a TypeScript/JSX source file instead
   of pre-built JavaScript. This catches the problem at site build time
   with an actionable message.

2. The `emdash bundle` command now validates that all package.json
   exports point to built files (.js/.mjs), not source (.ts/.tsx/.jsx).
   This catches the misconfiguration at plugin publish time, before
   consumers are affected.

Fixes #150

* chore: add changeset for sandbox source validation

* fix: use slash syntax for e18e rule override in oxlintrc

The test file override for e18e/prefer-static-regex used parenthesis
syntax ("e18e(prefer-static-regex)") which is the diagnostic display
format, not the config format. Changed to slash syntax to match the
top-level rule declarations so the override actually takes effect.

* test: add tests for sandbox source validation

Add tests for both validation checks:

- generateSandboxedPluginsModule: verifies it embeds pre-built JS,
  rejects .ts/.tsx/.mts source files, and includes the plugin ID in
  error messages.

- findSourceExports: verifies it flags .ts/.tsx/.mts/.cts/.jsx exports,
  accepts .mjs/.js exports, and handles conditional export maps.

Also extracts findSourceExports() from the inline bundle.ts validation
into bundle-utils.ts so it can be tested without the CLI harness.

* fix(atproto, audit-log): add build step and export built files

Same issue as webhook-notifier — both plugins exported raw TypeScript
source from their package.json sandbox exports. Add tsdown build steps
and update exports to point to dist/*.mjs.

* refactor(smoke): replace sequential per-site astro builds with recursive pnpm build

The build verification section was running `astro build` individually
and sequentially for every demo and template (~12 sites). Replace with
a single `pnpm run --recursive --filter {./demos/*} --filter
{./templates/*} build` which pnpm parallelizes automatically.

packages/plugins/audit-log/package.json

@@ -3,13 +3,16 @@
 	"version": "0.1.0",
 	"description": "Audit logging plugin for EmDash CMS - tracks content changes",
 	"type": "module",
-	"main": "src/index.ts",
+	"main": "dist/index.mjs",
 	"exports": {
-		".": "./src/index.ts",
-		"./sandbox": "./src/sandbox-entry.ts"
+		".": {
+			"import": "./dist/index.mjs",
+			"types": "./dist/index.d.mts"
+		},
+		"./sandbox": "./dist/sandbox-entry.mjs"
 	},
 	"files": [
-		"src"
+		"dist"
 	],
 	"keywords": [
 		"emdash",
@@ -21,12 +24,16 @@
 	],
 	"author": "Matt Kane",
 	"license": "MIT",
-	"dependencies": {},
-	"peerDependencies": {
+	"dependencies": {
 		"emdash": "workspace:*"
 	},
-	"devDependencies": {},
+	"devDependencies": {
+		"tsdown": "catalog:",
+		"typescript": "catalog:"
+	},
 	"scripts": {
+		"build": "tsdown src/index.ts src/sandbox-entry.ts --format esm --dts --clean",
+		"dev": "tsdown src/index.ts src/sandbox-entry.ts --format esm --dts --watch",
 		"typecheck": "tsgo --noEmit"
 	},
 	"optionalDependencies": {},