feat(amazonq): bundle stripped indexing folder for @file support in fallback LSP (#8591)

## 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)

Author: chungjac

scripts/lspArtifact.ts

@@ -152,7 +152,22 @@ export async function downloadLanguageServer(): Promise<void> {
 
                         // Clean up temp directory
                         fs.rmdirSync(tempDir)
-                        fs.rmdirSync(path.join(resourcesDir, 'servers', 'indexing'), { recursive: true })
+                        // Strip heavy native/model files from indexing, keep tree-sitter + extension.js
+                        const indexingDir = path.join(resourcesDir, 'servers', 'indexing')
+                        if (fs.existsSync(indexingDir)) {
+                            const binDir = path.join(indexingDir, 'dist', 'bin')
+                            if (fs.existsSync(binDir)) {
+                                fs.rmdirSync(binDir, { recursive: true })
+                            }
+                            const buildDir = path.join(indexingDir, 'dist', 'build')
+                            if (fs.existsSync(buildDir)) {
+                                fs.rmdirSync(buildDir, { recursive: true })
+                            }
+                            const modelsDir = path.join(indexingDir, 'models')
+                            if (fs.existsSync(modelsDir)) {
+                                fs.rmdirSync(modelsDir, { recursive: true })
+                            }
+                        }
                         fs.rmdirSync(path.join(resourcesDir, 'servers', 'ripgrep'), { recursive: true })
                         fs.rmSync(path.join(resourcesDir, 'servers', 'node'))
                         if (!fs.existsSync(path.join(resourcesDir, 'servers', 'aws-lsp-codewhisperer.js'))) {