chore(agents): remove all obsolete agent files

[fbeaudoincoveo]

Context

This PR is a follow up to:

• chore: rework AGENTS.md files #7133
• chore(agents): simplify AGENTS.md #7180
• chore(agents): add atomic-unit-testing Agent Skill #7186
• chore(agents): add managing-atomic-components Agent Skill #7190

What's Removed

• All remaining .instructions.md files - Reasoning: all useful instructions have been redistributed into AGENTS.md files or Agent Skills
• The following Agent Skills - Reasoning: we are now using AGENTS.md and Agent Skills exclusively:
  • creating-agents
  • creating-instructions
  • creating-prompts 
• The following .agent.md files:
  • accessibility-v1 - Reasoning: made obsolete by `applying-wcage-guidelines Agent Skill
  • prompt-engineer-v1 - Reasoning: made obsolete by prompt-engineer-v2; will be turned into an Agent Skill
  • refine-issue-v2 - Reasoning: was grabbed from awesome-copilot and likely never used
  • research-technical-spike-v2 - Reasoning: was grabbed from awesome-copilot and likely never used
  • review-component-migration-v1 - Reasoning: Stencil -> Lit component migration is over
  • stencil-to-lit-migration (v1 and v2) - Reasoning: Stencil -> Lit component migration is over
  • task-researcher-v1 - Reasoning: was grabbed from awesome-copilot and likely never used 
  • typescript-mcp-expert - Reasoning: made obsolete by creating-stories  Agent Skill

Next Steps

• Rework maintenance-v1.agent.md into Agent Skill
• Rework prompt-engineer-v2.agent.md into Agent Skill
• Remove remaining .agent.md files
• Rename .claude directory to .agents and update configs / references

https://coveord.atlassian.net/browse/KIT-5493

[github-actions]

🔗 Scratch Orgs ready to test this PR:

• ✅ LWS Enabled: Open Org
• ✅ LWS Disabled: Open Org

[Copilot]

Pull request overview

This PR removes a large number of obsolete AI agent/instruction configuration files from the repository as part of a cleanup effort. The project has transitioned to using AGENTS.md files and dedicated Agent Skills, making these older artifacts redundant.

Changes:

• Removes all .instructions.md files from .github/instructions/ (general, TypeScript, atomic, and Playwright-TypeScript guidelines), as their content has been redistributed into AGENTS.md or Agent Skills.
• Removes multiple .agent.md files that are superseded, migration-related (Stencil→Lit migration is complete), or were unused community-sourced agents.
• Removes the creating-agents, creating-prompts, and creating-instructions Claude skills and their associated scripts/references from .claude/skills/.
• Removes internal-docs/opencode-setup.md, the OpenCode CLI setup guide.

Reviewed changes

Copilot reviewed 35 out of 35 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
.github/instructions/general.instructions.md	Removed: general coding principles
.github/instructions/general.typescript.instructions.md	Removed: TypeScript-specific type safety/module rules
.github/instructions/atomic.instructions.md	Removed: Lit component conventions for the Atomic package
.github/instructions/playwright-typescript.instructions.md	Removed: Playwright E2E test writing guidelines
.github/agents/accessibility-v1.agent.md	Removed: superseded by applying-wcag-guidelines Agent Skill
.github/agents/prompt-engineer-v1.agent.md	Removed: superseded by v2 / will become an Agent Skill
.github/agents/refine-issue-v1.agent.md	Removed: community-sourced, reportedly unused
.github/agents/research-technical-spike-v1.agent.md	Removed: community-sourced, reportedly unused
.github/agents/review-component-migration-v1.agent.md	Removed: Stencil→Lit migration is complete
.github/agents/stencil-to-lit-migration-v1.agent.md	Removed: Stencil→Lit migration is complete
.github/agents/stencil-to-lit-migration-v2.agent.md	Removed: Stencil→Lit migration is complete
.github/agents/task-researcher-v1.agent.md	Removed: community-sourced, reportedly unused
.github/agents/typescript-mcp-expert-v1.agent.md	Removed: superseded by creating-stories Agent Skill
.claude/skills/creating-agents/	Removed: entire skill directory including scripts and references
.claude/skills/creating-prompts/	Removed: entire skill directory including scripts and references
.claude/skills/creating-instructions/	Removed: entire skill directory including scripts and references
internal-docs/opencode-setup.md	Removed: OpenCode CLI setup guide

Comments suppressed due to low confidence (2)

internal-docs/opencode-setup.md:1

• Deleting internal-docs/opencode-setup.md leaves a dangling reference in README.md (line 113), which links to this file as the OpenCode setup guide. The README.md section at lines 109–113 reads: "This repo includes configuration for the OpenCode CLI (including the Sisyphus agent). Setup guide: internal-docs/opencode-setup.md". After this deletion, that link will be broken. The README.md should be updated to remove or replace this reference.
  .github/instructions/general.instructions.md:1
• The opencode.json configuration file references both .github/instructions/general.instructions.md and .github/instructions/general.typescript.instructions.md in its "instructions" array (lines 6–7 of opencode.json). Both of these files are being deleted by this PR, which means OpenCode will fail to load its configured instructions after this change. The opencode.json should either be updated to remove these references or point to wherever the content was relocated (e.g., an AGENTS.md file).

[louis-bompart]