docs: document greet() return format and usage in overview.md

## What drifted

`src/hello.js` exports `greet(name)` which returns `` `Bonjour, ${name}!` ``. The source file even carries the comment:

> `/** Sample public helper — if you change this, update docs/overview.md */`

However, `docs/overview.md` only described the function as "returns a greeting string" — it did not document:
- the actual greeting format (`Bonjour, !`)
- the default value for `name` (`"world"`)
- example usage

## Changes

- Updated `docs/overview.md` to document the return value format, the `name` parameter default, and two usage examples.

## Reviewer checklist

- [ ] Confirm the greeting format (`Bonjour, ${name}!`) matches the current `src/hello.js` implementation.
- [ ] Verify examples are accurate.

> Generated by [Tier 1 / Docs drift (gh-aw)](https://github.com/bcgov/tier1-pattern-test/actions/runs/30244124113) · 20.4 AIC · ⌖ 4.9 AIC · ⊞ 5.1K · [◷](https://github.com/search?q=repo%3Abcgov%2Ftier1-pattern-test+%22gh-aw-workflow-id%3A+tier1-docs-drift%22&type=pullrequests)

---

> [!NOTE]
> This was originally intended as a pull request, but GitHub Actions is not permitted to create or approve pull requests in this repository.
> The changes have been pushed to branch `docs/fix-greet-overview-386e618d4b3e0a34`.
>
> **[Click here to create the pull request](https://github.com/bcgov/tier1-pattern-test/compare/main...docs/fix-greet-overview-386e618d4b3e0a34?expand=1&title=docs%3A%20document%20greet()%20return%20format%20and%20usage%20in%20overview.md)**

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Show patch (39 lines)

```diff
From bbb7910e199a4f9a9876ded49a5da9dd50fe3e1e Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
Date: Mon, 27 Jul 2026 06:54:05 +0000
Subject: [PATCH] docs: document greet() return format in overview

src/hello.js returns `Bonjour, ${name}!` but docs/overview.md
only said 'returns a greeting string'. Update to document the
actual return format, default parameter, and add usage examples.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
docs/overview.md | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/docs/overview.md b/docs/overview.md
index baa0f7d..1894a65 100644
--- a/docs/overview.md
+++ b/docs/overview.md
@@ -1,5 +1,14 @@
# Overview

-`greet(name)` returns a greeting string.
+`greet(name)` returns a greeting string in the form `"Bonjour, !"`.

-(Intentionally simple — change `src/hello.js` without updating this file to exercise docs drift.)
+- **Parameter**: `name` — string, defaults to `"world"`
+- **Returns**: `` `Bonjour, ${name}!` ``
+
+Example:
+
+```js
+import { greet } from "./src/hello.js";
+greet("Alice"); // → "Bonjour, Alice!"
+greet(); // → "Bonjour, world!"
+```
--
2.54.0

```

Read src/hello.js to confirm greet(name)'s return format and default, then review docs/overview.md against the stated documentation requirements. Verify the return description, parameter default, and both examples match the implementation; the issue includes a generated patch on branch docs/fix-greet-overview-386e618d4b3e0a34, so check whether that work has already been turned into a pull request.

Written by the indexing model from the issue text.