docs: describe remaining documentation pages (#3008)

website/src/next/docs/changelog.md

@@ -1,5 +1,8 @@
 ---
 title: Changelog
+description:
+  Release history for Task, including new features, improvements, fixes, and
+  breaking changes
 outline: deep
 editLink: false
 ---
@@ -1633,4 +1636,4 @@ document, since it describes in depth what changed for this version.
 
 - Add LICENSE file
 
-:::
+:::

website/src/next/docs/guide.md

@@ -1,4 +1,6 @@
 ---
+description:
+  Guide to running Taskfiles and using Task features in real-world workflows
 outline: deep
 ---
 

website/src/next/docs/remote-taskfiles.md

@@ -1,4 +1,6 @@
 ---
+description:
+  Guide to loading and securely using Taskfiles from HTTP and Git sources
 outline: deep
 ---
 

website/src/next/docs/security/incident-response-plan.md

@@ -1,5 +1,8 @@
 ---
 title: Incident Response Plan
+description:
+  Task's process for detecting, triaging, mitigating, and disclosing security
+  incidents
 outline: deep
 ---
 

website/src/next/docs/security/index.md

@@ -1,5 +1,8 @@
 ---
 title: Security
+description:
+  How to report Task security vulnerabilities and how the project responds to
+  them
 outline: deep
 ---
 

website/src/next/docs/security/threat-model.md

@@ -1,5 +1,8 @@
 ---
 title: Threat Model
+description:
+  Threats, assets, trust boundaries, and mitigations for the Task project and
+  its release infrastructure
 outline: deep
 ---