WIP: Save agent roles integration work before CHORUS rebrand

- Agent roles and coordination features
- Chat API integration testing
- New configuration and workspace management

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

vendor/github.com/multiformats/go-multihash/sum.go

@@ -0,0 +1,77 @@
+package multihash
+
+import (
+	"fmt"
+	"hash"
+	"io"
+
+	mhreg "github.com/multiformats/go-multihash/core"
+)
+
+// ErrSumNotSupported is returned when the Sum function code is not implemented
+var ErrSumNotSupported = mhreg.ErrSumNotSupported
+
+var ErrLenTooLarge = mhreg.ErrLenTooLarge
+
+// Sum obtains the cryptographic sum of a given buffer. The length parameter
+// indicates the length of the resulting digest. Passing a negative value uses
+// default length values for the selected hash function.
+func Sum(data []byte, code uint64, length int) (Multihash, error) {
+	// Get the algorithm.
+	hasher, err := mhreg.GetVariableHasher(code, length)
+	if err != nil {
+		return nil, err
+	}
+
+	// Feed data in.
+	if _, err := hasher.Write(data); err != nil {
+		return nil, err
+	}
+
+	return encodeHash(hasher, code, length)
+}
+
+// SumStream obtains the cryptographic sum of a given stream. The length
+// parameter indicates the length of the resulting digest. Passing a negative
+// value uses default length values for the selected hash function.
+func SumStream(r io.Reader, code uint64, length int) (Multihash, error) {
+	// Get the algorithm.
+	hasher, err := mhreg.GetVariableHasher(code, length)
+	if err != nil {
+		return nil, err
+	}
+
+	// Feed data in.
+	if _, err = io.Copy(hasher, r); err != nil {
+		return nil, err
+	}
+
+	return encodeHash(hasher, code, length)
+}
+
+func encodeHash(hasher hash.Hash, code uint64, length int) (Multihash, error) {
+	// Compute final hash.
+	//  A new slice is allocated.  FUTURE: see other comment below about allocation, and review together with this line to try to improve.
+	sum := hasher.Sum(nil)
+
+	// Deal with any truncation.
+	//  Unless it's an identity multihash.  Those have different rules.
+	if length < 0 {
+		length = hasher.Size()
+	}
+	if len(sum) < length {
+		return nil, ErrLenTooLarge
+	}
+	if length >= 0 {
+		if code == IDENTITY {
+			if length != len(sum) {
+				return nil, fmt.Errorf("the length of the identity hash (%d) must be equal to the length of the data (%d)", length, len(sum))
+			}
+		}
+		sum = sum[:length]
+	}
+
+	// Put the multihash metainfo bytes at the front of the buffer.
+	//  FUTURE: try to improve allocations here.  Encode does several which are probably avoidable, but it's the shape of the Encode method arguments that forces this.
+	return Encode(sum, code)
+}