test(terminal): stabilize double-click selection coverage

[kaluli123123]

Summary

• construct a confirmed Kind::Double before exercising selection release behavior
• bound construction retries to one second
• remove dependence on scheduler timing during coverage instrumentation

Root cause

The test created two clicks once and assumed both calls completed within iced's 300 ms double-click window. Under coverage instrumentation or host load, the second click could be classified as Single, causing an unrelated selection assertion to fail.

Verification

• reproduced during cargo llvm-cov before the change
• focused regression test: 20 consecutive passes
• cargo +nightly fmt
• cargo clippy --workspace --all-targets --all-features -- -D warnings
• cargo deny check
• cargo test --workspace --all-features: 526 passed, 2 ignored
• cargo llvm-cov --workspace --all-features --fail-under-lines 80: all tests passed; repository line coverage is 67.74%, below the existing 80% gate

Notes

cargo deny reports the existing yanked transitive dependencies core2 0.4.0 and spin 0.9.8.

[kaluli123123]

@coderabbitai review

Please focus on whether the bounded click construction removes timing dependence without weakening the behavioral assertion.