docs(qa): codify desktop integration baseline governance

Co-Authored-By: Paperclip <noreply@paperclip.ing>

plans/2026-03-31-hac-35-desktop-integration-baseline.md

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+# HAC-35 Desktop Integration Baseline
+
+Date: 2026-03-31 UTC
+Owner: CTO
+Issue: HAC-35
+Current QA branch: `cmp-35-desktop-integration-baseline`
+Base branch: `cmp-31-safe-mutation-guardrails`
+
+## Why This Exists
+
+- `cmp-22-db-switcher-hardening`, `cmp-28-connection-context-lifecycle`, and `cmp-30-inspector-readability-path` were already marked done, but they were not all present on the branch QA would actually pull for current desktop verification.
+- That mismatch made the control plane report "done" while the real testable branch still lagged behind.
+- `HAC-35` fixes the immediate branch state and establishes a stricter closure rule for future engineering issues.
+
+## Integrated Branch Result
+
+- Unified QA / manual-test branch: `cmp-35-desktop-integration-baseline`
+- Base preserved from `cmp-31-safe-mutation-guardrails` at `b6cbe5a`
+- Integrated source branches:
+  - `cmp-22-db-switcher-hardening` at `04da063`
+  - `cmp-30-inspector-readability-path` at `9697447`
+  - `cmp-28-connection-context-lifecycle` at `4839165`
+- Merge commits on the unified branch:
+  - `0edeb27` merged `cmp-22-db-switcher-hardening`
+  - `5b1cb35` merged `cmp-30-inspector-readability-path`
+  - `f890809` merged `cmp-28-connection-context-lifecycle`
+
+## Conflict Handling
+
+The source branches were not cleanly stacked. They overlapped on `App.tsx`, README / QA docs, and helper files that had already drifted on `cmp-31`.
+
+Resolution policy used for this integration:
+
+1. Keep the newer baseline content already present on `cmp-31` when it was strictly more complete.
+2. Reintroduce the missing finished feature slices from `cmp-22`, `cmp-28`, and `cmp-30`.
+3. Prefer the more complete helper implementation when duplicate helper files existed with near-identical intent.
+4. Keep QA and README text aligned to the integrated branch's actual test count and visible capability set.
+
+Net result:
+
+- DB switcher hardening from `HAC-22` is present on the integrated branch.
+- Inspector readability path from `HAC-30` is present on the integrated branch.
+- Connection-session lifecycle hardening from `HAC-28` is present on the integrated branch.
+- The integrated branch still preserves the later baseline work that already lived on `cmp-31`.
+
+## Verification
+
+Executed on `cmp-35-desktop-integration-baseline` after all merges resolved:
+
+- `pnpm --filter @redis-gui/desktop test`
+  - pass
+  - 12 files / 48 tests
+- `pnpm run desktop:build`
+  - pass
+
+## Current Operating Rule
+
+For the current desktop phase, QA and manual testing should pull `cmp-35-desktop-integration-baseline` instead of assembling multiple closed issue branches by hand.
+
+If a newer integration branch replaces it later, the replacing issue must update:
+
+- the current integration branch name
+- the merge result summary
+- the verification summary
+- the branch governance document
+
+## Future Closure Standard
+
+An engineering issue is not truly complete until all of the following are true:
+
+1. Scope implementation is complete on its working branch.
+2. The issue-level verification has passed and is recorded.
+3. The change has been merged into the designated integration baseline branch for its phase.
+4. The issue comment includes branch name, commit SHA, push target, verification summary, and known risk.
+5. QA can test the capability from one unified branch without manually composing other completed issue branches.
+
+If step 3 is missing, the issue may be code-complete, but it is not integration-complete and should not be treated as fully delivered.