feat: Phase 4 — reusable "subscribe" workflow (+ dogfood it) (#8)

Centralizes the consumer stub into a reusable Gitea workflow
(.gitea/workflows/review-reusable.yml, workflow_call + defaulted inputs +
secrets: inherit); gadfly's own dogfood is now a thin caller of it, which
proved end-to-end that github.event context propagates into the reusable
on this act_runner. Adds the slim examples/reusable.yml stub + docs.

Folded in the swarm's findings: timeout_minutes default 30->45, map
GADFLY_API_KEY, explicit permissions block, drop the dead specialist_suite
input, and harden the example's actor gate. ~70 findings graded.

Completes the gadfly-games build (Phases 1-4 + quality fixes).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Co-authored-by: Steve Dudenhoeffer <steve@stevedudenhoeffer.com>
Co-committed-by: Steve Dudenhoeffer <steve@stevedudenhoeffer.com>

examples/README.md

@@ -6,7 +6,8 @@ set the secrets/vars it references. Gadfly is advisory only — it never blocks
 
 | File | Backend | Needs |
 |------|---------|-------|
-| [`adversarial-review.yml`](adversarial-review.yml) | **Ollama Cloud** (default) + inline notes for every provider | secret `OLLAMA_CLOUD_API_KEY` |
+| [`reusable.yml`](reusable.yml) | **slimmest stub** — calls Gadfly's reusable workflow (`secrets: inherit`); take the defaults or override a few inputs | secret `OLLAMA_CLOUD_API_KEY` |
+| [`adversarial-review.yml`](adversarial-review.yml) | **Ollama Cloud** (default) + inline notes for every provider; full self-contained stub | secret `OLLAMA_CLOUD_API_KEY` |
 | [`local-ollama.yml`](local-ollama.yml) | a **local/LAN Ollama** daemon | nothing (or `GADFLY_BASE_URL` for a remote host) |
 | [`openai-compatible.yml`](openai-compatible.yml) | any **OpenAI-compatible** endpoint (local Ollama `/v1`, gateway, vLLM, OpenRouter…) | `GADFLY_BASE_URL` (+ a key for most gateways) |
 | [`endpoint-aliases.yml`](endpoint-aliases.yml) | **several named backends** at once (one comment each) | repo vars `GADFLY_ENDPOINT_<NAME>` |