[information-architecture] PR Actions Detective is documented as core but placed outside Core Workflows navigation

## Information Architecture Findings

### 1. Core workflow is misgrouped in docs navigation
**Area:** Grouping
**Component(s):** `mkdocs.yml`, `docs/index.md`, `docs/workflows/gh-agent-workflows.md`, `README.md`
**Problem:** Users are told that **PR Actions Detective** is one of the five core/default workflows, but the docs sidebar places it under **Repository Maintenance** instead of **Core Workflows**. This splits one concept across two categories and makes the core setup path harder to follow.

**Evidence:**
- `docs/index.md:50-59` lists the five core workflows and includes `PR Actions Detective`.
- `docs/workflows/gh-agent-workflows.md:28-30` defines the **Core (default)** set and includes `pr-actions-detective`.
- `README.md:25-26` includes `pr-actions-detective` in the starter/top recommended set.
- `mkdocs.yml:30-35` defines the **Core Workflows** nav section and omits `PR Actions Detective`.
- `mkdocs.yml:35-42` places `PR Actions Detective` under **Repository Maintenance**.

**Suggested improvement:** Align the taxonomy across homepage, workflow overview, README, and sidebar navigation. Either move `PR Actions Detective` into **Core Workflows** in `mkdocs.yml`, or reclassify it consistently everywhere if it is no longer core.

## Suggested Actions
- [ ] Update `mkdocs.yml` so category placement matches the declared core/default set.
- [ ] Reconcile any mismatched workflow-category references in `README.md`, `docs/index.md`, and `docs/workflows/gh-agent-workflows.md` to a single canonical grouping.

> [!NOTE]
>
> 🔒 Integrity filter blocked 3 items
>
> The following items were blocked because they don't meet the GitHub integrity level.
>
> - elastic/ai-github-actions#1067 `list_issues`: has lower integrity than agent requires. The agent cannot read data with integrity below "approved".
> - elastic/ai-github-actions#1025 `list_issues`: has lower integrity than agent requires. The agent cannot read data with integrity below "approved".
> - elastic/ai-github-actions#875 `list_issues`: has lower integrity than agent requires. The agent cannot read data with integrity below "approved".
>
> To allow these resources, lower `min-integrity` in your GitHub frontmatter:
>
> ```yaml
> tools:
> github:
> min-integrity: approved # merged | approved | unapproved | none
> ```
>
>

---
[What is this?](https://ela.st/github-ai-tools) | [From workflow: Trigger Information Architecture](https://github.com/elastic/ai-github-actions/actions/runs/26529327893)

Give us feedback! React with 🚀 if perfect, 👍 if helpful, 👎 if not.