Regenerate docs, update CHANGELOG for v1.0.0, clean up registry manifest

- Regenerated docs/ via tfplugindocs: 51 files covering all 20 resources
  and 30 data sources with auto-extracted schemas and examples
- Removed stale docs for old resources (build.md, ssh.md)
- CHANGELOG.md: added v1.0.0 entry with full feature list, breaking
  changes, and security notes
- terraform-registry-manifest.json: confirmed protocol_versions ["6.0"]
  is correct for Terraform Plugin Framework

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

docs/resources/ssh_key.md

@@ -0,0 +1,38 @@
+---
+# generated by https://github.com/hashicorp/terraform-plugin-docs
+page_title: "virtfusion_ssh_key Resource - virtfusion"
+subcategory: ""
+description: |-
+  Manages a VirtFusion SSH key.
+---
+
+# virtfusion_ssh_key (Resource)
+
+Manages a VirtFusion SSH key.
+
+## Example Usage
+
+```terraform
+resource "virtfusion_ssh_key" "mykey" {
+  user_id    = 1
+  name       = "my-ssh-key"
+  public_key = "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIExample user@example.com"
+}
+
+output "ssh_key_id" {
+  value = virtfusion_ssh_key.mykey.id
+}
+```
+
+<!-- schema generated by tfplugindocs -->
+## Schema
+
+### Required
+
+- `name` (String) The name of the SSH key.
+- `public_key` (String) The public key content.
+- `user_id` (Number) The ID of the user who owns this SSH key.
+
+### Read-Only
+
+- `id` (Number) The ID of the SSH key.