## Summary
- remove the complete Welcome guidance surface when dismissal reaches
`hidden`
- preserve dismissal across the private and starter Welcome channels for
the active identity
- assert the starter channel's actual `welcome-everyone` title on
re-entry
## Why
PR #5330 introduced two deterministic Desktop E2E failures:
- the inner banner unmounted, but `welcome-composer-guidance-layer`
remained
- the re-entry test expected case-sensitive `Welcome` while navigating
to `welcome-everyone`
The state hook also scoped completion to channel IDs while `ChannelPane`
remounts during navigation. The Welcome guidance is one experience
spanning both Welcome channels, so completion now survives that remount
while remaining identity-scoped.
## Validation
At `b577eb42edffe889f63566f2457eacea720f3593`:
- `pnpm -C desktop typecheck`
- focused Biome check for all four changed files
- E2E build
- both `welcome-everywhere banner` integration tests repeated three
times: **6/6 passed**
- mandatory pre-push desktop check, typecheck, and full desktop unit
suite: **4,535 passed**
- `git diff --check`
Signed-off-by: Wes <wesbillman@users.noreply.github.com>
Co-authored-by: Carl <c7ebe626f000404285d3686e1dc74cc07cc60a9754a150041ba132e14bd3e2ec@buzz.block.builderlab.xyz>
