feat: support Claude Code compatibility toggles

[kirillk]

What

• Add Claude Code slash command discovery from .claude/commands and mark Claude-origin slash commands.
• Add granular Claude compatibility settings for skills/commands and CLAUDE.md instructions across VS Code and JetBrains.
• Add a config-console Claude context detection endpoint and regenerate the SDK.
• Prompt VS Code users per repo when Claude context is detected, while deferring behind first-run onboarding.

Why

Kilo should support Claude Code skills and commands by default without re-enabling CLAUDE.md instructions by default, preserving existing custom-agent behavior while making compatibility controls explicit.

Notes

• Claude command frontmatter is parsed like Kilo commands, but Claude-only fields such as allowed-tools are not enforced.
• JetBrains includes the compatibility settings and slash badge plumbing; the per-repo context banner is implemented for VS Code.

Validation

• packages/opencode: targeted Claude/runtime/config-console tests passed.
• packages/opencode: bun run typecheck passed.
• packages/kilo-vscode: bun run typecheck, bun run lint, bun run test:unit, and bun run compile passed.
• packages/kilo-jetbrains: ./gradlew typecheck passed.
• repo root: bun run script/check-opencode-annotations.ts --worktree passed.

Caveats

• Full packages/opencode bun test timed out in existing snapshot tests.
• packages/kilo-jetbrains ./gradlew test exceeded the 120s local timeout while running backend tests.