feat(amazonq): bundle stripped indexing folder for @file support in fallback LSP

[chungjac]

Problem

When users behind corporate proxies/firewalls can't download the LSP from CDN, the extension falls back to a bundled LSP. The bundled LSP currently excludes the entire indexing/ folder (~200MB), which means @file, @folder, and @code context commands don't work for these users.

Solution

Instead of deleting the entire indexing folder during bundling, selectively strip only the heavy platform-specific files that aren't needed for context commands:

• dist/bin/ — ONNX native binaries (25MB)
• dist/build/ — faiss native binaries (11MB)
• models/ — CodeSage ONNX model (124MB)

This keeps extension.js, lspServer.js, tree-sitter WASMs (~30MB uncompressed, ~3MB compressed in VSIX), which is everything needed for @file, @folder, @code, and BM25 cross-file context.

VSIX size impact: +3MB (19MB → 22MB)

Depends on aws/language-servers#2629: (CDN must have the updated indexing library)

[amazon-inspector-ohio]

⏳ I'm reviewing this pull request for security vulnerabilities and code quality issues. I'll provide an update when I'm done

[github-actions]

• This pull request implements a feat or fix, so it must include a changelog entry (unless the fix is for an unreleased feature). Review the changelog guidelines.
  • Note: beta or "experiment" features that have active users should announce fixes in the changelog.
  • If this is not a feature or fix, use an appropriate type from the title guidelines. For example, telemetry-only changes should use the telemetry type.

[amazon-inspector-ohio]

✅ I finished the code review, and didn't find any security or code quality issues.