Replace local-only filtering in GitHub issue/PR picker dialogs with
server-side GitHub Search API queries. Search text is sent as a query
parameter to the server, which uses the GitHub Search API
(issuesAndPullRequests endpoint) with repo: qualifiers including fork
network support. Results are debounced at 350ms to respect API rate
limits.
- Add query parameter to GitHubAPI issuesList/prsList interface
- Server routes use Search API when query is present, standard list
endpoint when absent
- Fork networks handled via repo:owner/repo OR repo:owner/upstream
- PR search fetches full PR details after Search API for head/base/draft
fields
- Remove local filter memos from all three picker dialogs
- Add debounced search effect with abort controller cleanup
- Update VS Code backend and webview API for parity
- Update search placeholders in all locales
Closes#1350
Co-authored-by: Bohdan Triapitsyn <artmore@protonmail.com>
