feat(sdk): Effect v4 + @effect/openapi-generator; typed pf.api & example ladder

Drop Orval for the first-party @effect/openapi-generator (OpenAPI 3.1 ->
Effect Schema + a typed HttpClient client) and bump effect 3.19 ->
4.0.0-beta.98. Port the hand-written surfaces to the v4 API (Result over
Either, Context.Service, Codec, Literals/Union arrays, Stream/Schedule/
Effect renames). Transport (CA-pinning fetch) and the reconnecting SSE
source are kept intact.

Make the SDK approachable for non-Effect users:
- Add pf.api.* on the Promise facade: the generated client surfaced as
  typed, Promise-native methods (await pf.api.listPairedClients()), so REST
  calls are autocompleted and checked instead of stringly-typed
  pf.request(method, path, body) + `as` casts. Zero-drift veneer over
  make(httpClient), backed by the same pinning fetch. pf.request stays as
  the untyped escape hatch.
- Re-tier examples into a 1-4 complexity ladder, rewritten onto pf.api.*
  (the typed payloads caught a wrong `launch` shape in provider-sync);
  the Effect example is labelled advanced. Add examples/ to tsconfig so
  they are typechecked (stops rot).

typecheck + 19 tests green.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

sdk/package.json

@@ -9,18 +9,19 @@
 		"./effect": "./src/effect.ts"
 	},
 	"scripts": {
-		"gen": "orval --config ./orval.config.ts",
+		"gen": "openapigen --spec ../api/openapi.json --name Punktfunk --format httpclient > src/gen/punktfunk.ts",
 		"typecheck": "tsc --noEmit",
 		"test": "bun test",
 		"runner": "bun src/runner-cli.ts"
 	},
 	"dependencies": {
-		"effect": "^3.19.0"
+		"effect": "^4.0.0-beta.98"
 	},
 	"devDependencies": {
-		"orval": "^8.20.0",
-		"typescript": "^5.9.3",
-		"@types/bun": "^1.3.0"
+		"@effect/openapi-generator": "4.0.0-beta.98",
+		"@effect/platform-node": "4.0.0-beta.98",
+		"@types/bun": "^1.3.0",
+		"typescript": "^5.9.3"
 	},
 	"optionalDependencies": {
 		"undici": "^7.0.0"