fix: use Azurite-compatible URL format for signed_upload_url

[carjessu-trm]

Problem

actions/cache@v4.2.0+ (and any action using @actions/cache v4+) hardcodes useAzureSdk: true in saveCacheV2(). This passes the signed_upload_url returned by CreateCacheEntry to the Azure BlobClient constructor, which expects URLs in Azure Blob Storage format.

The current URL format:

{API_BASE_URL}/upload/{id}

…causes the Azure SDK to fail with:

Warning: Failed to save: Unable to extract blobName and containerName with provided information.

The upload handler already correctly handles Azure SDK requests (comp=blocklist, blockid query params), but the URL format prevents the BlobClient constructor from parsing it.

Solution

Change the upload URL to use Azurite-compatible format:

{API_BASE_URL}/devstoreaccount1/upload/{id}

The Azure SDK recognizes devstoreaccount1 as the Azurite storage emulator account name, and correctly extracts:

• accountName: devstoreaccount1
• containerName: upload
• blobName: {id}

The original /upload/{id} route is preserved for backward compatibility (e.g., tonistiigi/go-actions-cache used by Docker buildx).

Changes

1. CreateCacheEntry.post.ts: Updated signed_upload_url to include /devstoreaccount1 prefix
2. routes/devstoreaccount1/upload/[uploadId].put.ts: Added route handler at the Azurite-compatible path (identical to the existing upload handler)

Testing

Tested with:

• actions/cache@v4 (v4.3.0) — cache save succeeds
• actions/setup-node@v4 with cache: npm — cache save succeeds
• Self-hosted ARC runners on GKE with GCS storage driver
• enableDirectDownloads: true

Fixes #203

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