feat: add APort VS Code extension

[HamidA1998]

Summary

Closes #35 by adding a VS Code extension under tools/vscode-extension for APort policy and integration development.

The extension includes:

• APort-specific snippets for JavaScript, TypeScript, JSON/JSONC, and YAML
• JSON schema validation for APort policy and passport fixture files
• APort syntax highlighting for policy packs, agent IDs, capabilities, and common keys
• Completion items for policy keys, common policy packs, and capability names
• Example policy/passport files and a Next.js middleware example
• Extension documentation and a small manifest/schema validation test

Validation

• npm run compile
• npm test
• npm pack --dry-run
• git diff --check

[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Include aport-passport.json in APort document detection

The completion provider never treats aport-passport.json as an APort file because isLikelyAPortDocument only checks for .aport-passport.json and aport.passport.json. This conflicts with the extension manifest, which explicitly maps aport-passport.json in contributes.jsonValidation (tools/vscode-extension/package.json), so users creating that supported filename from scratch won’t get APort completions until content happens to match the fallback regex.

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