fix(core): remove duplicate root-level trace configuration (#2944)

### Proposed Changes

The Config struct had two places where tracing.Config was embedded:
- config.Config.Trace (root level) - UNUSED
- server.Config.Trace (under server) - ACTUALLY USED

Only cfg.Server.Trace was ever passed to tracing.InitTracer in start.go,
making the root-level Trace field dead code.

Changes:
- Remove unused Trace field from config.Config struct
- Remove unused tracing package import from config.go
- Fix docs to use correct server.trace.* paths instead of trace.*
- Move Tracing Configuration section under Server Configuration in docs
- Add YAML example showing correct configuration structure

### Checklist

- [ ] I have added or updated unit tests
- [ ] I have added or updated integration tests (if appropriate)
- [ ] I have added or updated documentation

### Testing Instructions

Author: strantalis

docs/Configuring.md

@@ -14,8 +14,8 @@ The platform leverages [viper](https://github.com/spf13/viper) to help load conf
       - [Additive Configuration](#additive-configuration)
       - [Programmatic Configuration](#programmatic-configuration)
     - [Crypto Provider](#crypto-provider)
-  - [Database Configuration](#database-configuration)
     - [Tracing Configuration](#tracing-configuration)
+  - [Database Configuration](#database-configuration)
   - [Security Configuration](#security-configuration)
   - [Services Configuration](#services-configuration)
     - [Key Access Server (KAS)](#key-access-server-kas)
@@ -252,6 +252,43 @@ Environment Variable: `OPENTDF_SERVER_CRYPTOPROVIDER_STANDARD='[{"alg":"rsa:2048
 | `cryptoProvider.standard.*.private` | Path to the private key as a PEM file.                                    |            |
 | `cryptoProvider.standard.*.cert`    | (Optional) Path to a public cert for the keypair.                         |            |
 
+### Tracing Configuration
+
+Root level key `server.trace`
+
+| Field                        | Description                     | Default | Environment Variable               |
+| ---------------------------- | ------------------------------- | ------- | ---------------------------------- |
+| `server.trace.enabled`       | Enable distributed tracing      | `false` | OPENTDF_SERVER_TRACE_ENABLED       |
+| `server.trace.provider.name` | Tracing provider (file or otlp) | `otlp`  | OPENTDF_SERVER_TRACE_PROVIDER_NAME |
+
+For file provider:
+- `server.trace.provider.file.path`: Path to trace file output
+- `server.trace.provider.file.prettyPrint`: Enable pretty-printed JSON
+- `server.trace.provider.file.maxSize`: Maximum file size in MB
+- `server.trace.provider.file.maxBackups`: Maximum number of backup files
+- `server.trace.provider.file.maxAge`: Maximum age of files in days
+- `server.trace.provider.file.compress`: Enable compression of trace files
+
+For OTLP provider:
+- `server.trace.provider.otlp.protocol`: Protocol to use (grpc or http/protobuf)
+- `server.trace.provider.otlp.endpoint`: Endpoint URL for the collector
+- `server.trace.provider.otlp.insecure`: Whether to use an insecure connection
+- `server.trace.provider.otlp.headers`: Headers to include in OTLP requests
+
+Example:
+
+```yaml
+server:
+  trace:
+    enabled: true
+    provider:
+      name: otlp
+      otlp:
+        protocol: grpc
+        endpoint: "localhost:4317"
+        insecure: true
+```
+
 ## Database Configuration
 
 The database configuration is used to define how the application connects to its database.
@@ -302,27 +339,6 @@ db:
     health_check_period_seconds: 60
 ```
 
-### Tracing Configuration
-
-| Field                 | Description                     | Default | Environment Variable               |
-| --------------------- | ------------------------------- | ------- | ---------------------------------- |
-| `trace.enabled`       | Enable distributed tracing      | `false` | OPENTDF_SERVER_TRACE_ENABLED       |
-| `trace.provider.name` | Tracing provider (file or otlp) | `otlp`  | OPENTDF_SERVER_TRACE_PROVIDER_NAME |
-
-For file provider:
-- `trace.provider.file.path`: Path to trace file output
-- `trace.provider.file.prettyPrint`: Enable pretty-printed JSON
-- `trace.provider.file.maxSize`: Maximum file size in MB
-- `trace.provider.file.maxBackups`: Maximum number of backup files
-- `trace.provider.file.maxAge`: Maximum age of files in days
-- `trace.provider.file.compress`: Enable compression of trace files
-
-For OTLP provider:
-- `trace.provider.otlp.protocol`: Protocol to use (grpc or http/protobuf)
-- `trace.provider.otlp.endpoint`: Endpoint URL for the collector
-- `trace.provider.otlp.insecure`: Whether to use an insecure connection
-- `trace.provider.otlp.headers`: Headers to include in OTLP requests
-
 ## Security Configuration
 
 Root level key `security`

service/pkg/config/config.go

@@ -11,7 +11,6 @@ import (
 	"github.com/opentdf/platform/service/internal/server"
 	"github.com/opentdf/platform/service/logger"
 	"github.com/opentdf/platform/service/pkg/db"
-	"github.com/opentdf/platform/service/tracing"
 	"github.com/spf13/viper"
 )
 
@@ -90,9 +89,6 @@ type Config struct {
 	// Services represents the configuration settings for the services.
 	Services ServicesMap `mapstructure:"services" json:"services"`
 
-	// Trace is for configuring open telemetry based tracing.
-	Trace tracing.Config `mapstructure:"trace" json:"trace"`
-
 	// onConfigChangeHooks is a list of functions to call when the configuration changes.
 	onConfigChangeHooks []ChangeHook
 	// loaders is a list of configuration loaders.