feat(coding-agent/tools): added examples to coding-agent tools

- Added `examples` support to `StringEnum` schemas and propagated it to tool metadata.
- Added concise descriptions and example values across coding-agent tool schemas for clearer guidance.
- Documented the new StringEnum examples capability in `packages/ai/CHANGELOG.md`.
- Cast `real` to `HASHLINE_BIGRAMS` elements in `staleBigramFor` test setup.

packages/coding-agent/src/tools/ssh.ts

@@ -22,10 +22,10 @@ import { toolResult } from "./tool-result";
 import { clampTimeout } from "./tool-timeouts";
 
 const sshSchema = Type.Object({
-	host: Type.String({ description: "Host name from managed SSH config or discovered ssh.json files" }),
-	command: Type.String({ description: "Command to execute on the remote host" }),
-	cwd: Type.Optional(Type.String({ description: "Remote working directory (optional)" })),
-	timeout: Type.Optional(Type.Number({ description: "Timeout in seconds", default: 60 })),
+	host: Type.String({ description: "ssh host", examples: ["my-server", "prod-1"] }),
+	command: Type.String({ description: "remote command", examples: ["ls -la", "uptime"] }),
+	cwd: Type.Optional(Type.String({ description: "remote working directory", examples: ["/var/log"] })),
+	timeout: Type.Optional(Type.Number({ description: "timeout in seconds", default: 60 })),
 });
 
 export interface SSHToolDetails {