fix(cli): limit provider selector height

[michaelneale]

This builds on top of PR: #10474 as an example

Caps the goose configure provider picker at 10 visible rows so the provider list is no longer too long to navigate. Fixes #10415.

Why

On goose configure, the provider selector rendered every provider (35+) at once because cliclack::select shows all items unless max_rows is set, making the list unwieldy.

How

• Cap the selector at MAX_PROVIDER_ROWS = 10 via .max_rows(10).
• For long lists, insert a "Search all providers..." entry that opens a dedicated fuzzy-search step (jaro-winkler similarity + word-match bonus), with a "Search again..." escape hatch. cliclack 0.5.5 doesn't reset its internal list offset when filtering a paginated select, so a separate search step is used rather than inline filter_mode for long lists.
• Short lists (≤10) keep the original filter_mode behaviour.
• Move the currently-configured provider into view if it would fall outside the visible window.
• Provider entries are modeled with a ProviderChoice enum (Provider(String) / Search / SearchAgain) rather than sentinel string keys, so the picker's control flow is checked by the compiler and real providers can never collide with UI actions.

Testing

• cargo fmt / cargo clippy -p goose-cli --lib clean
• cargo test -p goose-cli — unit tests for the fuzzy filter and view-window logic pass
• Ran goose configure end-to-end: provider screen shows 10 rows with "Search all providers..." as the last entry, arrow-key scrolling works, and the search flow filters correctly.