feat: Auto-generate and edit session display names (#432)

## Summary

Two-part feature for session display name management:

### 1. Auto-Generate Display Names
When users send their first message in a session, the backend
automatically generates a descriptive display name using Claude Haiku.

- Triggers on first user message when `displayName` is empty
- Uses session context (repos, workflow) to generate relevant names
- Runs asynchronously - fails silently with logging on error
- Supports both Anthropic API (via project secret) and Google Vertex AI

### 2. Manual Name Editing
Added UI controls to edit session names:
- "Edit name" option in session detail page kebab menu
- "Edit name" option in sessions list actions dropdown
- Simple modal dialog for editing

### Backend Changes
- Added `handlers/display_name.go` with Claude Haiku integration
- Added `PUT
/api/projects/:projectName/agentic-sessions/:sessionName/displayname`
endpoint
- Modified `PostSessionMessageWS` to trigger auto-generation
- Added Anthropic Go SDK with Vertex AI support

### Frontend Changes
- Added `EditSessionNameDialog` component
- Added `useUpdateSessionDisplayName` React Query mutation
- Added Next.js API proxy route for display name updates
- Updated `session-header.tsx` and `sessions-section.tsx` with edit
buttons

### Testing
- Tested manual name editing via UI
- Verified backend deployment with Vertex AI authentication fix

Author: Gkrumbach07

components/backend/go.mod

@@ -5,6 +5,7 @@ go 1.24.0
 toolchain go1.24.7
 
 require (
+	github.com/anthropics/anthropic-sdk-go v1.2.0
 	github.com/gin-contrib/cors v1.7.6
 	github.com/gin-gonic/gin v1.10.1
 	github.com/golang-jwt/jwt/v5 v5.3.0
@@ -18,15 +19,20 @@ require (
 )
 
 require (
+	cloud.google.com/go/auth v0.7.2 // indirect
+	cloud.google.com/go/auth/oauth2adapt v0.2.3 // indirect
+	cloud.google.com/go/compute/metadata v0.5.0 // indirect
 	github.com/bytedance/sonic v1.13.3 // indirect
 	github.com/bytedance/sonic/loader v0.2.4 // indirect
 	github.com/cloudwego/base64x v0.1.5 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/emicklei/go-restful/v3 v3.12.2 // indirect
+	github.com/felixge/httpsnoop v1.0.4 // indirect
 	github.com/fxamacker/cbor/v2 v2.9.0 // indirect
 	github.com/gabriel-vasile/mimetype v1.4.9 // indirect
 	github.com/gin-contrib/sse v1.1.0 // indirect
 	github.com/go-logr/logr v1.4.2 // indirect
+	github.com/go-logr/stdr v1.2.2 // indirect
 	github.com/go-openapi/jsonpointer v0.21.0 // indirect
 	github.com/go-openapi/jsonreference v0.20.2 // indirect
 	github.com/go-openapi/swag v0.23.0 // indirect
@@ -35,7 +41,11 @@ require (
 	github.com/go-playground/validator/v10 v10.26.0 // indirect
 	github.com/goccy/go-json v0.10.5 // indirect
 	github.com/gogo/protobuf v1.3.2 // indirect
+	github.com/golang/groupcache v0.0.0-20210331224755-41bb18bfe9da // indirect
+	github.com/golang/protobuf v1.5.4 // indirect
 	github.com/google/gnostic-models v0.7.0 // indirect
+	github.com/google/s2a-go v0.1.7 // indirect
+	github.com/googleapis/enterprise-certificate-proxy v0.3.2 // indirect
 	github.com/josharian/intern v1.0.0 // indirect
 	github.com/json-iterator/go v1.1.12 // indirect
 	github.com/klauspost/cpuid/v2 v2.2.10 // indirect
@@ -49,19 +59,33 @@ require (
 	github.com/pkg/errors v0.9.1 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/spf13/pflag v1.0.6 // indirect
+	github.com/tidwall/gjson v1.14.4 // indirect
+	github.com/tidwall/match v1.1.1 // indirect
+	github.com/tidwall/pretty v1.2.1 // indirect
+	github.com/tidwall/sjson v1.2.5 // indirect
 	github.com/twitchyliquid64/golang-asm v0.15.1 // indirect
 	github.com/ugorji/go/codec v1.3.0 // indirect
 	github.com/x448/float16 v0.8.4 // indirect
+	go.opencensus.io v0.24.0 // indirect
+	go.opentelemetry.io/contrib/instrumentation/google.golang.org/grpc/otelgrpc v0.49.0 // indirect
+	go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.49.0 // indirect
+	go.opentelemetry.io/otel v1.24.0 // indirect
+	go.opentelemetry.io/otel/metric v1.24.0 // indirect
+	go.opentelemetry.io/otel/trace v1.24.0 // indirect
 	go.yaml.in/yaml/v2 v2.4.2 // indirect
 	go.yaml.in/yaml/v3 v3.0.4 // indirect
 	golang.org/x/arch v0.18.0 // indirect
 	golang.org/x/crypto v0.45.0 // indirect
 	golang.org/x/net v0.47.0 // indirect
 	golang.org/x/oauth2 v0.27.0 // indirect
+	golang.org/x/sync v0.18.0 // indirect
 	golang.org/x/sys v0.38.0 // indirect
 	golang.org/x/term v0.37.0 // indirect
 	golang.org/x/text v0.31.0 // indirect
 	golang.org/x/time v0.9.0 // indirect
+	google.golang.org/api v0.189.0 // indirect
+	google.golang.org/genproto/googleapis/rpc v0.0.0-20240722135656-d784300faade // indirect
+	google.golang.org/grpc v1.64.1 // indirect
 	google.golang.org/protobuf v1.36.6 // indirect
 	gopkg.in/evanphx/json-patch.v4 v4.12.0 // indirect
 	gopkg.in/inf.v0 v0.9.1 // indirect