feat: URL-derived provider keys (hs-<hostname>) + dedup providers sharing same gateway URL

- GatewayProviderKey() derives stable key from gateway URL hostname
  e.g. https://llmgw.h.raczylo.com/v1 → hs-llmgw-h-raczylo-com
- AbsorbDuplicateProviders() merges providers sharing the same baseURL
  into our canonical entry; user-crafted model metadata wins for overlaps
- kilo: renders to opencode.jsonc (primary config), deep-merges providers,
  deletes enabled_providers filter that was hiding our gateway
- opencode: absorbs duplicate providers from existing config
- All adapters use GatewayProviderKey() instead of hardcoded string
- Fix goose URL doubling (was /v1/v1/chat/completions → /chat/completions)
- Fix token propagation: api_key written directly (not env var ref)
- Zed: adds prompt_cache_key capability, deletes context_servers key
  to avoid ContextServerSettingsContent serde untagged-enum parse error

internal/adapters/kilo/kilo.go

@@ -126,14 +126,18 @@ func (a *Adapter) Render(b *canonical.Bundle) (*adapter.FileSet, error) {
 			"enabled_providers": nil, // delete filter
 		}
 
-		// Deep-merge provider: add our entries INTO the existing provider map.
+		// Deep-merge provider: add our entries INTO the existing provider map,
+		// then absorb any duplicate providers that share the same gateway URL.
 		if newProv, ok := overlay["provider"].(map[string]any); ok && len(newProv) > 0 {
-			existing, _ := ocBase["provider"].(map[string]any)
-			if existing == nil {
-				existing = map[string]any{}
+			existingProv, _ := ocBase["provider"].(map[string]any)
+			if existingProv == nil {
+				existingProv = map[string]any{}
 			}
-			maps.Copy(existing, newProv)
-			ocOverlay["provider"] = existing
+			maps.Copy(existingProv, newProv)
+			// Absorb providers at the same URL into harness-sync-gateway,
+			// preserving user-crafted display names and custom limits.
+			merged := common.AbsorbDuplicateProviders(existingProv, common.GatewayProviderKey(b.Profile.Gateway.URL), b.Profile.Gateway.URL)
+			ocOverlay["provider"] = merged
 		}
 		// Copy model/small_model/mcp from the kilo.json overlay.
 		for _, k := range []string{"model", "small_model", "mcp"} {

internal/adapters/kilo/kilo_test.go

@@ -43,12 +43,12 @@ func TestKiloRender(t *testing.T) {
 	var parsed map[string]any
 	require.NoError(t, json.Unmarshal(seen[cfgDest].Content, &parsed))
 	// model is "providerID/modelID" string.
-	assert.Equal(t, "harness-sync-gateway/sonnet", parsed["model"])
-	assert.Equal(t, "harness-sync-gateway/sonnet", parsed["small_model"])
+	assert.Equal(t, "hs-gw/sonnet", parsed["model"])
+	assert.Equal(t, "hs-gw/sonnet", parsed["small_model"])
 	// provider map present with npm field.
 	provider, ok := parsed["provider"].(map[string]any)
 	require.True(t, ok, "provider must be a map")
-	gw, ok := provider["harness-sync-gateway"].(map[string]any)
+	gw, ok := provider["hs-gw"].(map[string]any)
 	require.True(t, ok)
 	assert.Equal(t, "@ai-sdk/openai-compatible", gw["npm"])
 	assert.Contains(t, parsed, "mcp")
@@ -113,14 +113,14 @@ func TestKiloRenderEmitsModelString(t *testing.T) {
 	var parsed map[string]any
 	require.NoError(t, json.Unmarshal(seen[cfgDest].Content, &parsed))
 
-	// model must be "harness-sync-gateway/<modelID>".
-	assert.Equal(t, "harness-sync-gateway/claude-sonnet-4-6", parsed["model"])
-	assert.Equal(t, "harness-sync-gateway/claude-sonnet-4-6", parsed["small_model"])
+	// model must be "hs-gw/<modelID>".
+	assert.Equal(t, "hs-gw/claude-sonnet-4-6", parsed["model"])
+	assert.Equal(t, "hs-gw/claude-sonnet-4-6", parsed["small_model"])
 
 	// provider map has npm field.
 	provider, ok := parsed["provider"].(map[string]any)
 	require.True(t, ok)
-	gw, ok := provider["harness-sync-gateway"].(map[string]any)
+	gw, ok := provider["hs-gw"].(map[string]any)
 	require.True(t, ok)
 	assert.Equal(t, "@ai-sdk/openai-compatible", gw["npm"])
 	opts, ok := gw["options"].(map[string]any)
@@ -165,9 +165,9 @@ func TestKiloRenderMergesOpenCodeJSONC(t *testing.T) {
 	// llmgw preserved, harness-sync-gateway added.
 	provider := parsed["provider"].(map[string]any)
 	assert.Contains(t, provider, "llmgw")
-	assert.Contains(t, provider, "harness-sync-gateway")
+	assert.Contains(t, provider, "hs-gw")
 	// model updated.
-	assert.Equal(t, "harness-sync-gateway/sonnet", parsed["model"])
+	assert.Equal(t, "hs-gw/sonnet", parsed["model"])
 }
 
 func TestKiloImport(t *testing.T) {