docs: format root README packages as a table (#9)

Replace the per-package heading + badge + prose list with a single
Package / Version / What it does table. The root README is an index —
each package ships its own README — so a scannable directory reads better.

Change-Id: I71ee7e657e992d59a5daaaef9395878109f4a66d

Signed-off-by: Thomas Kosiewski <tk@coder.com>
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: ThomasK33

README.md

@@ -13,32 +13,11 @@ agents inside Coder workspaces, and drive Coder Agents from AI SDK code.
 Each package is published to npm independently and ships its own README with full
 install instructions, usage, and API docs.
 
-### [`@coder/ai-sdk-sandbox`](./packages/sandbox)
-
-[![npm](https://img.shields.io/npm/v/@coder/ai-sdk-sandbox.svg)](https://www.npmjs.com/package/@coder/ai-sdk-sandbox)
-
-A **sandbox provider** for the Vercel AI SDK v7 `HarnessAgent`. It runs CLI coding
-agents — Claude Code, Codex — inside a **Coder workspace** instead of on the local
-machine, so each agent gets a real, isolated dev environment with your tools,
-secrets, and network.
-
-### [`@coder/ai-sdk-agent`](./packages/agent)
-
-[![npm](https://img.shields.io/npm/v/@coder/ai-sdk-agent.svg)](https://www.npmjs.com/package/@coder/ai-sdk-agent)
-
-A Vercel AI SDK–compliant **`Agent`** (AI SDK v6) backed by **Coder Agents**,
-Coder's server-side agent runtime. `new CoderAgent()` returns a real `Agent` —
-`generate()`, `stream()`, tool calls, the whole interface.
-
-### [`@coder/ai-sdk-provider`](./packages/provider)
-
-[![npm](https://img.shields.io/npm/v/@coder/ai-sdk-provider.svg)](https://www.npmjs.com/package/@coder/ai-sdk-provider)
-
-A **Vercel AI SDK provider** that routes `generateText` / `streamText` calls
-through your Coder deployment's
-[AI Gateway](https://coder.com/docs/ai-coder/ai-gateway). Point it at your
-deployment with a Coder API token and use any model it proxies — no raw provider
-keys, with per-user auth and audit.
+| Package                                         | Version                                                                                                                 | What it does                                                                                                                                                                                                                                                                                                 |
+| ----------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
+| [`@coder/ai-sdk-sandbox`](./packages/sandbox)   | [![npm](https://img.shields.io/npm/v/@coder/ai-sdk-sandbox.svg)](https://www.npmjs.com/package/@coder/ai-sdk-sandbox)   | A **sandbox provider** for the Vercel AI SDK v7 `HarnessAgent`. Runs CLI coding agents — Claude Code, Codex — inside a **Coder workspace** instead of on the local machine, so each agent gets a real, isolated dev environment with your tools, secrets, and network.                                       |
+| [`@coder/ai-sdk-agent`](./packages/agent)       | [![npm](https://img.shields.io/npm/v/@coder/ai-sdk-agent.svg)](https://www.npmjs.com/package/@coder/ai-sdk-agent)       | A Vercel AI SDK–compliant **`Agent`** (AI SDK v6) backed by **Coder Agents**, Coder's server-side agent runtime. `new CoderAgent()` returns a real `Agent` — `generate()`, `stream()`, tool calls, the whole interface.                                                                                      |
+| [`@coder/ai-sdk-provider`](./packages/provider) | [![npm](https://img.shields.io/npm/v/@coder/ai-sdk-provider.svg)](https://www.npmjs.com/package/@coder/ai-sdk-provider) | A **Vercel AI SDK provider** that routes `generateText` / `streamText` calls through your Coder deployment's [AI Gateway](https://coder.com/docs/ai-coder/ai-gateway). Point it at your deployment with a Coder API token and use any model it proxies — no raw provider keys, with per-user auth and audit. |
 
 ## Contributing