docs(ship): Gitea releases created for v1.21.0..v1.21.6 + PPTX attached

All 7 Gitea releases created (ids 621-627) after fixing the token
variable name mismatch (config: ACDL_GITEA_TOKEN vs env:
NOVA_GITEA_TOKEN). Tags pushed to origin. PPTX attached to milestone
release v1.21.6 (asset id 98).

Release URLs: https://git.cloudinit.dev/continuous-intelligence/acdl/releases

---ci---
project: acdl
phase: 6
milestone: v1.22
status: complete
phase_role: final
---/ci---

.ciagent/CHECKPOINT.json

@@ -1,12 +1,28 @@
 {
-  "phase": 5,
+  "phase": 6,
   "stage": "complete",
   "milestone": "v1.22",
-  "phase_role": "execution",
+  "phase_role": "final",
   "attempts": 0,
-  "updated_at": "2026-08-11T15:10:00Z",
-  "milestone_complete": false,
-  "tag": "v1.21.5",
-  "requirements": ["REQ-262"],
-  "notes": "v1.22 P5 complete. Tag v1.21.5. HTML+PPTX re-rendered (22 slides, 23 media). 9 new layout/aspect-ratio/theme-structural tests added. 32 slide tests pass, 94 key-file tests pass, pipeline check exit 0. Proceeding to P6 (final review + audit + milestone ship)."
+  "updated_at": "2026-08-11T15:30:00Z",
+  "milestone_complete": true,
+  "tag": "v1.21.6",
+  "requirements": ["REQ-254","REQ-255","REQ-256","REQ-257","REQ-258","REQ-259","REQ-260","REQ-261","REQ-262"],
+  "release": {
+    "forge": "gitea",
+    "releases_created": true,
+    "release_ids": {
+      "v1.21.0": 621,
+      "v1.21.1": 622,
+      "v1.21.2": 623,
+      "v1.21.3": 624,
+      "v1.21.4": 625,
+      "v1.21.5": 626,
+      "v1.21.6": 627
+    },
+    "milestone_release_id": 627,
+    "pptx_asset_id": 98,
+    "pptx_download_url": "https://git.cloudinit.dev/attachments/fe691962-4f4e-4321-ab5d-c2bb8c3fd6ad"
+  },
+  "notes": "v1.22 milestone complete. Tag v1.21.6 (milestone release). Merged to main + pushed to origin. All 7 Gitea releases created (ids 621-627). PPTX attached to milestone release (asset id 98). All milestone branches deleted. 9 requirements complete (REQ-254..262). 32 slide tests pass (23 original + 9 new). 94 key-file tests pass. Pipeline check exit 0. Next milestone starts fresh."
 }