feat: rename attribute agent skill

[sudomateo]

Added a rename-attribute AI agent skill to, hopefully, allow an AI agent to do future renames of Terraform attributes.

Amp-Thread: https://ampcode.com/threads/T-019b4ea0-eacf-759c-8f7e-0746094eea36

[sudomateo]

Currently testing this on a commit that does not already have the changes in #578. See the attached Amp thread for more information.

Here's the diff it produced so far.

diff --git a/internal/provider/resource_instance.go b/internal/provider/resource_instance.go
index d9c344db26..6ad726f282 100644
--- a/internal/provider/resource_instance.go
+++ b/internal/provider/resource_instance.go
@@ -54,7 +54,8 @@
        Description        types.String                      `tfsdk:"description"`
        DiskAttachments    types.Set                         `tfsdk:"disk_attachments"`
        ExternalIPs        []instanceResourceExternalIPModel `tfsdk:"external_ips"`
-       HostName           types.String                      `tfsdk:"host_name"`
+       Hostname           types.String                      `tfsdk:"hostname"`
+       HostNameDeprecated types.String                      `tfsdk:"host_name"`
        ID                 types.String                      `tfsdk:"id"`
        Memory             types.Int64                       `tfsdk:"memory"`
        Name               types.String                      `tfsdk:"name"`
@@ -137,12 +138,32 @@
                                        stringplanmodifier.RequiresReplace(),
                                },
                        },
+                       "hostname": schema.StringAttribute{
+                               Optional:    true,
+                               Computed:    true,
+                               Description: "Host name of the instance.",
+                               PlanModifiers: []planmodifier.String{
+                                       stringplanmodifier.RequiresReplace(),
+                               },
+                               Validators: []validator.String{
+                                       stringvalidator.ExactlyOneOf(
+                                               path.MatchRoot("host_name"),
+                                       ),
+                               },
+                       },
                        "host_name": schema.StringAttribute{
-                               Required:    true,
-                               Description: "Host name of the instance.",
+                               Optional:           true,
+                               Computed:           true,
+                               Description:        "Deprecated: Use hostname instead.",
+                               DeprecationMessage: "Use hostname instead.",
                                PlanModifiers: []planmodifier.String{
                                        stringplanmodifier.RequiresReplace(),
                                },
+                               Validators: []validator.String{
+                                       stringvalidator.ExactlyOneOf(
+                                               path.MatchRoot("hostname"),
+                                       ),
+                               },
                        },
                        "memory": schema.Int64Attribute{
                                Required:    true,
@@ -362,12 +383,19 @@
        ctx, cancel := context.WithTimeout(ctx, createTimeout)
        defer cancel()

+       var hostname string
+       if !plan.Hostname.IsNull() && !plan.Hostname.IsUnknown() {
+               hostname = plan.Hostname.ValueString()
+       } else {
+               hostname = plan.HostNameDeprecated.ValueString()
+       }
+
        params := oxide.InstanceCreateParams{
                Project: oxide.NameOrId(plan.ProjectID.ValueString()),
                Body: &oxide.InstanceCreate{
                        Description: plan.Description.ValueString(),
                        Name:        oxide.Name(plan.Name.ValueString()),
-                       Hostname:    oxide.Hostname(plan.HostName.ValueString()),
+                       Hostname:    oxide.Hostname(hostname),
                        Memory:      oxide.ByteCount(plan.Memory.ValueInt64()),
                        Ncpus:       oxide.InstanceCpuCount(plan.NCPUs.ValueInt64()),
                        Start:       plan.StartOnCreate.ValueBoolPointer(),
@@ -468,6 +496,8 @@
        plan.ID = types.StringValue(instance.Id)
        plan.TimeCreated = types.StringValue(instance.TimeCreated.String())
        plan.TimeModified = types.StringValue(instance.TimeModified.String())
+       plan.Hostname = types.StringValue(string(instance.Hostname))
+       plan.HostNameDeprecated = types.StringValue(string(instance.Hostname))

        // Populate NIC information
        for i := range plan.NetworkInterfaces {
@@ -548,7 +578,8 @@
                state.AutoRestartPolicy = types.StringValue(string(instance.AutoRestartPolicy))
        }
        state.Description = types.StringValue(instance.Description)
-       state.HostName = types.StringValue(string(instance.Hostname))
+       state.Hostname = types.StringValue(string(instance.Hostname))
+       state.HostNameDeprecated = types.StringValue(string(instance.Hostname))
        state.ID = types.StringValue(instance.Id)
        state.Memory = types.Int64Value(int64(instance.Memory))
        state.Name = types.StringValue(string(instance.Name))
@@ -809,6 +840,8 @@
        plan.ProjectID = types.StringValue(instance.ProjectId)
        plan.TimeCreated = types.StringValue(instance.TimeCreated.String())
        plan.TimeModified = types.StringValue(instance.TimeModified.String())
+       plan.Hostname = types.StringValue(string(instance.Hostname))
+       plan.HostNameDeprecated = types.StringValue(string(instance.Hostname))

        // We use the plan here instead of the state to capture the desired IP pool ID
        // value for the ephemeral external IP rather than the previous value.