ci: improve rust-cache configuration for 100 GB cache limit

[Madoshakalaka]

Description

• Remove all shared-key parameters from Swatinem/rust-cache, letting each job use the default add-job-id-key for per-job cache isolation
• Add save-if: ${{ github.ref == 'refs/heads/master' }} so only master builds save caches (PRs restore from master but don't save)
• Fix step ordering in doc_tests and integration_tests so rust-cache runs after toolchain setup (as required by the action's README)

Background

PR #3520 identified that using shared-key causes unrelated jobs to share cache entries, leading to suboptimal cache usage. However, the fix was blocked by the 10 GB cache size limit.

PR #3711 then intentionally added shared-key everywhere to minimize the number of cache entries, trading cache accuracy for smaller total size.

Now that the GitHub Actions cache limit has been raised to 100 GB (thanks to @siku2 ), we can afford per-job caching. This PR revisits the approach from #3520 and goes further:

[github-actions]

Benchmark - core

Yew Master

vnode           fastest       │ slowest       │ median        │ mean          │ samples │ iters
╰─ vnode_clone  2.435 ns      │ 2.67 ns       │ 2.438 ns      │ 2.446 ns      │ 100     │ 1000000000

Pull Request

vnode           fastest       │ slowest       │ median        │ mean          │ samples │ iters
╰─ vnode_clone  2.436 ns      │ 3.68 ns       │ 2.439 ns      │ 2.454 ns      │ 100     │ 1000000000

[github-actions]

Visit the preview URL for this PR (updated for commit ddc3500):

https://yew-rs--pr4038-fix-rust-cache-confi-wc1045dl.web.app

_{(expires Tue, 10 Mar 2026 11:46:20 GMT)}

_{🔥 via Firebase Hosting GitHub Action 🌎}

[github-actions]

Size Comparison

Details

examples	master (KB)	pull request (KB)	diff (KB)	diff (%)
async_clock	100.197	100.197	0	0.000%
boids	168.080	168.080	0	0.000%
communication_child_to_parent	93.472	93.472	0	0.000%
communication_grandchild_with_grandparent	105.248	105.248	0	0.000%
communication_grandparent_to_grandchild	101.609	101.609	0	0.000%
communication_parent_to_child	90.899	90.899	0	0.000%
contexts	105.151	105.151	0	0.000%
counter	86.282	86.282	0	0.000%
counter_functional	88.276	88.276	0	0.000%
dyn_create_destroy_apps	90.320	90.320	0	0.000%
file_upload	99.346	99.346	0	0.000%
function_delayed_input	94.374	94.374	0	0.000%
function_memory_game	172.943	172.943	0	0.000%
function_router	406.410	406.410	0	0.000%
function_todomvc	164.160	164.160	0	0.000%
futures	235.159	235.159	0	0.000%
game_of_life	104.718	104.718	0	0.000%
immutable	255.879	255.879	0	0.000%
inner_html	80.803	80.803	0	0.000%
js_callback	109.379	109.379	0	0.000%
keyed_list	179.728	179.728	0	0.000%
mount_point	84.146	84.146	0	0.000%
nested_list	113.059	113.059	0	0.000%
node_refs	91.526	91.526	0	0.000%
password_strength	1729.146	1729.146	0	0.000%
portals	93.034	93.034	0	0.000%
router	376.976	376.976	0	0.000%
suspense	113.464	113.464	0	0.000%
timer	88.634	88.634	0	0.000%
timer_functional	98.877	98.877	0	0.000%
todomvc	142.088	142.088	0	0.000%
two_apps	86.146	86.146	0	0.000%
web_worker_fib	136.239	136.239	0	0.000%
web_worker_prime	187.470	187.470	0	0.000%
webgl	83.224	83.224	0	0.000%

✅ None of the examples has changed their size significantly.

[github-actions]

Benchmark - SSR

Yew Master

Details

Benchmark	Round	Min (ms)	Max (ms)	Mean (ms)	Standard Deviation
Baseline	10	296.710	314.426	308.296	4.962
Hello World	10	468.964	481.336	477.633	4.050
Function Router	10	30681.113	31797.483	31353.218	358.949
Concurrent Task	10	1005.360	1008.159	1006.667	0.783
Many Providers	10	1084.942	1133.533	1113.689	18.263

Pull Request

Details

Benchmark	Round	Min (ms)	Max (ms)	Mean (ms)	Standard Deviation
Baseline	10	290.094	311.070	304.555	7.604
Hello World	10	477.900	512.543	494.711	14.432
Function Router	10	30126.233	31180.332	30646.940	362.983
Concurrent Task	10	1005.456	1007.571	1006.537	0.643
Many Providers	10	1045.338	1132.216	1101.022	30.141