feat: add Cursor CLI agent across all clouds (#3018)

* feat: add Cursor CLI agent across all clouds

Adds Cursor's terminal-based AI coding agent (the `agent` command from
cursor.com/cli) to the spawn matrix. Routes LLM requests through
OpenRouter via --endpoint flag and CURSOR_API_KEY env var.

- manifest.json: new cursor agent entry + all 6 cloud matrix entries
- agent-setup.ts: install, configure, launch, and update definitions
- Shell scripts for all 6 clouds (local, hetzner, aws, do, gcp, sprite)
- Config: writes ~/.cursor/cli-config.json with full permissions
- Icon: cursor.png from cursor.com/apple-touch-icon.png
- All cloud READMEs updated with cursor.sh usage
- CLI version bumped to 0.26.0

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* feat: add spawn skill injection for Cursor CLI

Writes a .cursor/rules/spawn.mdc rule file with alwaysApply: true
during setup, teaching the Cursor agent how to use the spawn CLI
to provision child cloud VMs. Uses the same base64 upload pattern
as other agent config files.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

---------

Signed-off-by: Ahmed Abushagur <ahmed@abushagur.com>
Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Co-authored-by: A <258483684+la14-1@users.noreply.github.com>

sh/gcp/README.md

@@ -54,6 +54,12 @@ bash <(curl -fsSL https://openrouter.ai/labs/spawn/gcp/hermes.sh)
 bash <(curl -fsSL https://openrouter.ai/labs/spawn/gcp/junie.sh)
 ```
 
+#### Cursor CLI
+
+```bash
+bash <(curl -fsSL https://openrouter.ai/labs/spawn/gcp/cursor.sh)
+```
+
 ## Non-Interactive Mode
 
 ```bash