fix(docs): rebuild the mangled repository-structure tree

The tree block was hard-wrapped by the AsciiDoc->Markdown conversion, so it
rendered as a paragraph rather than a tree, and it still listed
CONTRIBUTING.md at the repository root, where the guide no longer lives.

Rebuilt from the tree's own content: depth recovered from the `|` continuation
bars that survived the wrap, the guide entry moved under `.github/`, `#`
escapes unescaped, the last entry of each group restored to `└──`, and the
block fenced so it renders as a tree. Every annotation ("Perimeter 1-2") is
preserved - nothing is invented and nothing is dropped.

Author: hyperpolymath

.github/CONTRIBUTING.md

@@ -20,19 +20,34 @@ just test    # Run test suite
 
 ### Repository Structure
 
-developer-ecosystem/ ├── src/ # Source code (Perimeter 1-2) ├── lib/ #
-Library code (Perimeter 1-2) ├── extensions/ # Extensions (Perimeter 2)
-├── plugins/ # Plugins (Perimeter 2) ├── tools/ # Tooling (Perimeter
-2) ├── docs/ # Documentation (Perimeter 3) │ ├── architecture/ # ADRs,
-specs (Perimeter 2) │ └── proposals/ # RFCs (Perimeter 3) ├── examples/
-# Examples (Perimeter 3) ├── spec/ # Spec tests (Perimeter 3) ├──
-tests/ # Test suite (Perimeter 2-3) ├── .well-known/ # Protocol files
-(Perimeter 1-3) ├── .github/ # GitHub config (Perimeter 1) │ ├──
-ISSUE_TEMPLATE/ │ └── workflows/ ├── CHANGELOG.md ├── CODE_OF_CONDUCT.md
-├── CONTRIBUTING.md # This file ├── GOVERNANCE.md ├── LICENSE ├──
-MAINTAINERS.md ├── README.adoc ├── SECURITY.md ├── flake.nix # Nix
-flake (Perimeter 1) └── Justfile # Task runner (Perimeter 1)
-
+```text
+developer-ecosystem/
+├── src/ # Source code (Perimeter 1-2)
+├── lib/ # Library code (Perimeter 1-2)
+├── extensions/ # Extensions (Perimeter 2)
+├── plugins/ # Plugins (Perimeter 2)
+├── tools/ # Tooling (Perimeter 2)
+├── docs/ # Documentation (Perimeter 3)
+│   ├── architecture/ # ADRs, specs (Perimeter 2)
+│   └── proposals/ # RFCs (Perimeter 3)
+├── examples/ # Examples (Perimeter 3)
+├── spec/ # Spec tests (Perimeter 3)
+├── tests/ # Test suite (Perimeter 2-3)
+├── .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
+├── GOVERNANCE.md
+├── LICENSE
+├── MAINTAINERS.md
+├── README.adoc
+├── SECURITY.md
+├── flake.nix # Nix flake (Perimeter 1)
+└── Justfile # Task runner (Perimeter 1)
+```
 
     ---