chore: retire Roo Code integration — extension shut down (#3167) (#3212)

* chore: retire roo integration — extension shut down (#3167)

Remove the Roo Code integration after the extension was shut down: subpackage,
registry entry, catalog entry, docs, tests, and issue-template options.

Assisted-by: GitHub Copilot (model: Claude Opus 4.8, autonomous)
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* docs: remove stale Roo Code mention in upgrade guide

Assisted-by: GitHub Copilot (model: gpt-5.3-codex, autonomous)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* chore: remove leftover Roo Code references after merge

Drop roo from presets/ARCHITECTURE.md example and the agent-context
defaults map; these came in from main and were flagged by review.

Assisted-by: GitHub Copilot (model: claude-opus-4.8, autonomous)

---------

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

tests/integrations/test_integration_roo.py

@@ -1,10 +0,0 @@
-"""Tests for RooIntegration."""
-
-from .test_integration_base_markdown import MarkdownIntegrationTests
-
-
-class TestRooIntegration(MarkdownIntegrationTests):
-    KEY = "roo"
-    FOLDER = ".roo/"
-    COMMANDS_SUBDIR = "commands"
-    REGISTRAR_DIR = ".roo/commands"

tests/integrations/test_registry.py

@@ -22,7 +22,7 @@ ALL_INTEGRATION_KEYS = [
     "copilot",
     # Stage 3 — standard markdown integrations
     "claude", "qwen", "opencode", "junie", "kilocode", "auggie",
-    "roo", "rovodev", "codebuddy", "qodercli", "amp", "shai", "bob", "trae",
+    "rovodev", "codebuddy", "qodercli", "amp", "shai", "bob", "trae",
     "pi", "kiro-cli", "vibe", "cursor-agent", "firebender",
     # Stage 4 — TOML integrations
     "gemini", "tabnine",