refactor(client): remove redundant location spreads - #47086

Why

Six location updates copy the entire cached location record before passing it to Solid's store setter. That setter already shallow-merges the provided record, so these copies repeat work and obscure which field the update owns.

What Changes

Publish only the changed location field, matching the existing locationResource helper:

// Before
setStore("location", key, { ...store.location[key], websearch: providers.data })

// After
setStore("location", key, { websearch: providers.data })

Apply this to connection preload, credential switching, branch updates, shell creation/removal, and websearch refresh. Preserve the nested shell-map and branch spreads: unlike the outer location spreads, those carry fields the replacement value still needs.

Scope

packages/client/src/solid/data.ts: +2 / −9, net −7 production lines. No helper, state, dependency, public interface, or request-scheduling change.

The existing client test file gains 98 lines covering cold shell-event initialization, sibling catalog and shell identity, retained branch metadata, request counts, and sibling preservation during credential events across locations/workspaces. These checks pass against both the original implementation and the deletion, including the focused browser-Solid run.

Verification

With Bun 1.4.0, from the indicated package directories:

# packages/client
bun run test
bun run test --conditions=browser test/solid-data.test.ts -t 'preserves sibling catalogs|refreshes global credential'
bun typecheck
bun run build
bunx prettier --check src/solid/data.ts test/solid-data.test.ts

# packages/tui
bun run test test/cli/tui/data.test.tsx

# packages/app
bun run test

• Client: 147 passed; the two focused browser-condition checks also passed before and after the production change. Typecheck and package build passed.
• TUI data suite: 46 passed.
• App: 717 unit passed, 1 skipped; 113 browser-runtime passed.
• The normal pre-push hook completed all 33 workspace typecheck tasks.
• An exploratory whole-file --conditions=browser run before the production change exposed two existing assertions in the assistant-content replacement and user-shell metadata tests. The normal configured client suite passes; those unrelated browser-condition assertions are not changed here.
• No performance improvement is claimed beyond removing redundant object construction and setter inputs. There is no visible UI change or new fetch policy.