docs: add decision traceability governance

docs/reference/strategy-governance.md

@@ -1,6 +1,6 @@
 # Strategy Governance
 
-This document owns the strategic filter for UniDesk requirements: external-benefit traceability, short-term versus long-term investment, and anti-loop guardrails for architecture proposals. The analysis record for the current strategy framing is [GitHub issue #7](https://github.com/pikasTech/unidesk/issues/7).
+This document owns the strategic filter for UniDesk requirements: external-benefit traceability, short-term versus long-term investment, and anti-loop guardrails for architecture proposals. The analysis record for the current strategy framing is [GitHub issue #7](https://github.com/pikasTech/unidesk/issues/7). The long-term governance follow-up for the default user path versus diagnostics/status boundary is `DC-DCSN-P0-2026-004`.
 
 ## Scope
 
@@ -98,6 +98,12 @@ When a new idea is proposed, classify it immediately:
 
 The default bias should be toward the simplest path that satisfies the external need. Complexity is only justified when it pays for itself in visible external value.
 
+## Default Path Boundary
+
+When a product surface has both a primary user workflow and an internal diagnostics or acceptance surface, the primary workflow must remain the default discoverable entry. Diagnostics and status pages may exist for verification, recovery, or observability, but they do not become the product's headline or default route unless a decision record explicitly says so.
+
+For the current HWLAB case, `DC-DCSN-P0-2026-003` freezes the short-term product direction, and `DC-DCSN-P0-2026-004` records the longer-term governance rule for keeping the default path distinct from diagnostics/status surfaces.
+
 ## Relationship to Other Governance Docs
 
 - `docs/reference/release-governance.md` owns release lines, stabilization windows, runtime pinning, and feature-flag governance.