feat(cloudflare): add linearvoid-media edge worker for R2 HLS delivery

Replace the ad-hoc `worker.js` with a self-contained `linearvoid-media`
worker under `infrastructure/cloudflare/` that owns `media.linearvoid.tv`.
It serves HLS objects from the R2 bucket, enforcing immutable Cache-Control
on segments, a short TTL on live manifests, plus HLS CORS, OPTIONS
preflight, Range support, and a `/health` probe. Includes wrapper config
with production domain, Vitest unit tests, Miniflare R2 integration tests,
automated deploy workflow, and docs updates.

docs/operations/gitea-cloudflare-workers.md

@@ -16,7 +16,7 @@ Deploy the Linear Void frontend (Vite + TypeScript SPA) from Gitea to Cloudflare
 3. **Account ID** from Cloudflare dashboard overview → store as `CLOUDFLARE_ACCOUNT_ID`
 4. **Wrangler config** (`frontend/wrangler.toml`) binding the `frontend/dist` output as static assets.
 
-> **Naming conflict:** Workers share a namespace under "Workers & Pages". The edge-cache Worker (`infrastructure/cloudflare/worker.js`) already uses the `linearvoid` name, so the SPA Worker is named `linearvoid-frontend` (see `frontend/wrangler.toml`).
+> **Naming:** Workers share a namespace under "Workers & Pages". The media edge Worker is `linearvoid-media` ([`infrastructure/cloudflare/`](../../infrastructure/cloudflare/wrangler.toml), deployed via `.gitea/workflows/workers-media-deploy.yml`) and the SPA Worker is `linearvoid-frontend` (`frontend/wrangler.toml`, deployed via `.gitea/workflows/workers-deploy.yml`).
 
 ## Project-specific values