fix(yew-link): surface initial internal fetch errors instead of retrying indefinitely

[cuishuang]

Description

Fix the client-side use_linked_state retry loop caused by initial LinkError::Internal results not being cached.

Initial fetches now cache all completed results, including infrastructure errors. This allows the suspension to resolve and exposes the error through LinkedStateHandle::as_result() instead of creating another identical request.

Refresh behavior remains unchanged: LinkError::Internal results from background refreshes are not cached, so an existing stale value is preserved.

Fixes #4218

Checklist

• I have reviewed my own code
• I have added tests

[github-actions]

Visit the preview URL for this PR (updated for commit d19c797):

https://yew-rs-api--pr4219-master-68tx4rnl.web.app

_{(expires Mon, 14 Sep 2026 14:34:33 GMT)}

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[github-actions]

Size Comparison

Details

examples	master (KB)	pull request (KB)	diff (KB)	diff (%)
async_clock	100.392	100.392	0	0.000%
boids	165.085	165.085	0	0.000%
communication_child_to_parent	93.856	93.856	0	0.000%
communication_grandchild_with_grandparent	106.241	106.241	0	0.000%
communication_grandparent_to_grandchild	102.563	102.563	0	0.000%
communication_parent_to_child	91.244	91.244	0	0.000%
contexts	106.551	106.551	0	0.000%
counter	86.417	86.417	0	0.000%
counter_functional	88.549	88.549	0	0.000%
dyn_create_destroy_apps	90.316	90.316	0	0.000%
file_upload	98.724	98.724	0	0.000%
function_delayed_input	94.864	94.864	0	0.000%
function_memory_game	168.840	168.840	0	0.000%
function_router	400.435	400.435	0	0.000%
function_todomvc	165.240	165.240	0	0.000%
futures	236.103	236.103	0	0.000%
game_of_life	100.787	100.787	0	0.000%
immutable	258.186	258.186	0	0.000%
inner_html	80.927	80.927	0	0.000%
js_callback	109.995	109.995	0	0.000%
keyed_list	176.485	176.485	0	0.000%
mount_point	84.341	84.341	0	0.000%
nested_list	112.891	112.891	0	0.000%
node_refs	91.923	91.923	0	0.000%
password_strength	1765.898	1765.898	0	0.000%
portals	93.743	93.743	0	0.000%
router	366.669	366.669	0	0.000%
suspense	114.180	114.180	0	0.000%
timer	88.663	88.663	0	0.000%
timer_functional	99.664	99.664	0	0.000%
todomvc	142.141	142.141	0	0.000%
two_apps	86.321	86.321	0	0.000%
web_worker_fib	136.737	136.737	0	0.000%
web_worker_prime	186.822	186.822	0	0.000%
webgl	83.073	83.073	0	0.000%

✅ None of the examples has changed their size significantly.