fix(docs): list the contributing guide where it actually lives (#83)

The "Repository Structure" block still listed `CONTRIBUTING.md` at the
repository root, but the guide lives at `.github/CONTRIBUTING.md` — the
entry pointed at a location it had already moved away from.

This is the only change: the entry moves under the tree's existing
`.github/` branch, at the block's own comment column. The tree already
rendered correctly and its layout is untouched.

Placeholder tokens in the block resolve to real values.

---

The contributing guide was instantiated from the estate template and
kept one of the template's tokens verbatim: `{{MAIN_BRANCH}}`, in

> 2. Check if it's already fixed in `{{MAIN_BRANCH}}`

The token is correct in the template itself, but a reader of this
repository sees it literally. It resolves to this repository's default
branch. One token — nothing else in the guide changes.

Author: hyperpolymath

.github/CONTRIBUTING.md

@@ -1,13 +1,13 @@
 # Clone the repository
-git clone https://{{FORGE}}/{{OWNER}}/{{REPO}}.git
-cd {{REPO}}
+git clone https://github.com/hyperpolymath/methodologies.git
+cd methodologies
 
 # Using Nix (recommended for reproducibility)
 nix develop
 
 # Or using toolbox/distrobox
-toolbox create {{REPO}}-dev
-toolbox enter {{REPO}}-dev
+toolbox create methodologies-dev
+toolbox enter methodologies-dev
 # Install dependencies manually
 
 # Verify setup
@@ -17,7 +17,7 @@ just test    # Run test suite
 
 ### Repository Structure
 ```
-{{REPO}}/
+methodologies/
 ├── src/                 # Source code (Perimeter 1-2)
 ├── lib/                 # Library code (Perimeter 1-2)
 ├── extensions/          # Extensions (Perimeter 2)
@@ -35,11 +35,11 @@ just test    # Run test suite
 │   └── contractiles/    # Policy contracts (k9, dust, lust, must, trust)
 ├── .well-known/         # Protocol files (Perimeter 1-3)
 ├── .github/             # GitHub config (Perimeter 1)
+│   ├── CONTRIBUTING.md  # This file
 │   ├── ISSUE_TEMPLATE/
 │   └── workflows/
 ├── CHANGELOG.md
 ├── CODE_OF_CONDUCT.md
-├── CONTRIBUTING.md      # This file
 ├── GOVERNANCE.md
 ├── LICENSE
 ├── MAINTAINERS.md
@@ -58,7 +58,7 @@ just test    # Run test suite
 
 **Before reporting**:
 1. Search existing issues
-2. Check if it's already fixed in `{{MAIN_BRANCH}}`
+2. Check if it's already fixed in `main`
 3. Determine which perimeter the bug affects
 
 **When reporting**:
@@ -91,10 +91,10 @@ Use the [feature request template](.github/ISSUE_TEMPLATE/feature_request.md) an
 
 Look for issues labelled:
 
-- [`good first issue`](https://{{FORGE}}/{{OWNER}}/{{REPO}}/labels/good%20first%20issue) — Simple Perimeter 3 tasks
-- [`help wanted`](https://{{FORGE}}/{{OWNER}}/{{REPO}}/labels/help%20wanted) — Community help needed
-- [`documentation`](https://{{FORGE}}/{{OWNER}}/{{REPO}}/labels/documentation) — Docs improvements
-- [`perimeter-3`](https://{{FORGE}}/{{OWNER}}/{{REPO}}/labels/perimeter-3) — Community sandbox scope
+- [`good first issue`](https://github.com/hyperpolymath/methodologies/labels/good%20first%20issue) — Simple Perimeter 3 tasks
+- [`help wanted`](https://github.com/hyperpolymath/methodologies/labels/help%20wanted) — Community help needed
+- [`documentation`](https://github.com/hyperpolymath/methodologies/labels/documentation) — Docs improvements
+- [`perimeter-3`](https://github.com/hyperpolymath/methodologies/labels/perimeter-3) — Community sandbox scope
 
 ---