feat: add public one-line remote installer for DeepSQL

Add scripts/self-host/remote-install.sh for OpenCode-style one-liner install:
  curl -fsSL https://raw.githubusercontent.com/.../remote-install.sh | bash

Features:
- Detects OS/arch (Linux, macOS, x86_64, arm64)
- Checks for bash, curl, git prerequisites
- Validates Docker Engine, Compose v2, and buildx (with version checks)
- Guides to bootstrap-server.sh if Docker is missing on Linux
- Clones to ${DEEPSQL_HOME:-$HOME/deepsql} at latest v* release tag
- Falls back to main branch if no release tags exist
- Copies .env.example to .env if needed
- Prints clear LLM configuration instructions (DEEPSQL_CHAT_*)
- Supports --yes for noninteractive install, --branch for specific versions
- Security: only fetches from GitHub raw/API for DeepSQLAI org

Also updates README Quick start with the one-liner + link to script.

Co-authored-by: Venkat SF <venkatesh.sakamuri@stayflexi.com>

Author: cursoragent

README.md

@@ -23,6 +23,18 @@ DeepSQL Desktop first ship + Agent/Brain/Editor hardening. Notes:
 
 ## Quick start
 
+### One-liner install
+
+```bash
+curl -fsSL https://raw.githubusercontent.com/DeepSQLAI/deepsql/main/scripts/self-host/remote-install.sh | bash
+```
+
+This checks prerequisites, clones the latest release to `~/deepsql`, and guides you
+through configuration. See [`scripts/self-host/remote-install.sh`](scripts/self-host/remote-install.sh)
+for options (`--yes` for noninteractive, `--branch` for a specific version).
+
+### Step-by-step
+
 Five steps, in order. Budget about fifteen minutes, most of it waiting on the first build.
 
 ### 1. Check you have what you need