Add Render Blueprint for one-click deployment

### Self Checks

- [x] I have read the [Contributing Guide](https://github.com/langgenius/dify/blob/main/CONTRIBUTING.md) and [Language Policy](https://github.com/langgenius/dify/issues/1542).
- [x] I have searched for existing issues [search for existing issues](https://github.com/langgenius/dify/issues), including closed ones.
- [x] I confirm that I am using English to submit this report, otherwise it will be closed.
- [x] Please do not modify this template :) and fill in all the required fields.

### 1. Is this request related to a challenge you're experiencing? Tell me about your story.

Dify already documents one-click deployment paths for Railway, Alibaba Cloud, AWS CDK, Terraform, and AKS, but not for [Render](https://render.com). Users who want a managed platform with Blueprint-based infrastructure-as-code currently have to hand-roll Docker services, Postgres, Redis, env wiring, and storage themselves.

A `render.yaml` Blueprint at the repo root would let users deploy `dify-api`, `dify-worker`, `dify-web`, Redis, and PostgreSQL (with pgvector) from upstream with consistent env vars, shared file storage, and automated pgvector extension setup.

### 2. Additional context or comments

Proposed scope:
- Add `render.yaml` Blueprint (Docker images, env var wiring, health checks, shared disk, PG 16 pin for uuidv7 migration compatibility)
- Add "Deploy on Render" section and button to `README.md` and localized READMEs
- Deploy button and Blueprint deeplink should point at `https://github.com/langgenius/dify`

Related closed PR: #32505 (closed for missing linked issue, not for technical rejection)

### 3. Can you help us with this feature?

- [x] I am interested in contributing to this feature.

Start by reviewing existing deployment documentation and the repository's Docker deployment setup, then compare the environment variables and health checks required by the API, worker, and web services. The proposed work names a root-level render.yaml and README.md/localized READMEs; verify the Blueprint provisions the listed services, shared storage, and PostgreSQL 16 with pgvector, and includes a working Render deploy link.

Written by the indexing model from the issue text.