docs: PRD rev1 re-review — repoint PRD heading anchors to GOV.4, complete archive line cites

Addresses CPS-PRD-REV1-REREVIEW findings on PR #1491 head 13968e9a:

F1 (blocker; the CI test failure): docs/PRD.md is now the permanent shim, so
heading-fragment links into the former PRD body no longer resolve —
fleet-documentation.spec.ts failed on docs/fleet/README.md's FCM anchor. The
Part II workstream contracts live in
docs/PRDs/2026-08-31_PRD_rev1/GOV.4-workstream-contracts.md; all five anchored
links in the tree are repointed there (fleet/README.md, TASKS.md,
release-integrity/TASKS.md, ADMIN-GUIDE mos-connector-lease-operations.md,
DEVELOPER-GUIDE mos-runtime-portability-m1.md). Each anchor verified against
the GOV.4 headings with the spec's slug rule. Bundle content unchanged.

F2 (minor): the rev0 archive README's ./ROADMAP.md row now cites all three
source lines (18, 177, 249).

docs/release-integrity/TASKS.md

@@ -8,7 +8,7 @@ status: active
 > Single-writer: the RI-050 orchestrator (jarvis, dragon-lin) only. Workers read but never modify.
 >
 > **Mission:** alpha 0.0.50 release-integrity floor (decisions SDLC-D-033..038).
-> **PRD:** [docs/PRD.md § Release Integrity Workstream](../PRD.md#release-integrity-workstream-ri-1275)
+> **PRD:** [PRD rev1 GOV.4 § Release Integrity Workstream](../PRDs/2026-08-31_PRD_rev1/GOV.4-workstream-contracts.md#release-integrity-workstream-ri-1275)
 > **Issue:** #1275 (remains open until RI-V-001 closes)
 > **Base branch:** `next` (all cards branch from `origin/next`, squash-merge via PR)
 >