chore: remove unused agentic files and audit research docs (#2191)

* chore: remove unused agentic instruction files and audit research docs

Remove .github/instructions/ (PRD/task workflow files unused since
Claude Code skills replaced the Copilot-era workflow). Update CLAUDE.md
and contributing.md references. Add status info boxes to all research
docs and reorganise the research README into clearer categories.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* chore: add changelog entry for PR #2191

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>

Author: 3 people

.changelog/pr-2191.txt

@@ -0,0 +1 @@
+chore: remove unused agentic files and audit research docs - by @IsmaelMartinez (#2191)

.github/instructions/create-prd.instructions.md

@@ -210,9 +210,6 @@ if (modulesRequiringIpc.includes(module.name)) {
 
 ## AI Workflow Instructions
 
-For AI agent workflows (PRD generation, task list generation, task execution):
-- See `.github/instructions/*.instructions.md` for detailed workflow instructions
-- Follow the task execution protocol for systematic implementation
 - Always run tests and linting before commits
 - Update documentation alongside code changes
 

.github/instructions/generate-tasks.instructions.md

@@ -250,8 +250,6 @@ When creating or updating any markdown documentation in this project (including
 These markdown standards apply to ALL markdown files in the project:
 - Documentation site (`docs-site/docs/`)
 - Root-level documentation (README, CONTRIBUTING, CLAUDE.md)
-- Task management files (`tasks/`)
-- AI agent instruction files (`.github/instructions/`)
 - Module READMEs in `app/` directories
 
 When updating standards, update this section only. All other files should reference these standards.