feat(timeout): add dynamic duration hooks

[thomhurst]

Summary

• add context-aware awaited TimeoutGenerator with per-execution validation
• add ordered OnTimeoutAsync after cleanup and the synchronous notification
• preserve caller-cancellation arbitration, exception identity, typed/sync execution, and pooled-context lifetime
• document callback ordering, concurrency, cancellation, and synchronous blocking semantics
• add fixed, sync-generated, truly async-generated, and async-hook-configured benchmarks

Part of #75.

Validation

• dotnet build Kevlar.slnx -c Release (0 warnings/errors)
• unit: 541 passed
• integration: 16 passed
• analyzers: 19 passed
• netstandard: 1 passed
• allocation: 2 passed
• npm run build
• Verify-Packages.ps1
• Verify-DocSnippets.ps1 (82 snippets)

Benchmarks

BenchmarkDotNet ShortRun, .NET 10.0.11, x64:

• fixed timeout: 109.0 ns / 0 B before; 112.2 ns / 0 B after (+2.9%, overlapping confidence intervals)
• synchronous generator: 120.2 ns / 0 B
• async hook configured, happy path: 116.8 ns / 0 B
• truly asynchronous generator: 1.116 us / 687 B

Closes #86

[coderabbitai]

Warning

Review limit reached

@thomhurst, you've reached your PR review limit, so we couldn't start this review.

Next review available in: 8 minutes

Limit details: You’ve used all 10 included reviews currently available.

Enable usage-based reviews in Billing to review now. Otherwise, wait until the next included review is available.
You're only billed for reviews past your plan's rate limits ($0.25/file).

How can I continue?

Wait for the limit to reset, then comment @coderabbitai review or push new commits to the PR.

An organization admin can change what happens after included review limits in Billing.

How do review limits work?

CodeRabbit enforces per-developer PR review limits within each organization.

For paid Pro and Pro+ reviews, CodeRabbit uses a developer's included PR review attempts over the past 7 days to set the current hourly allowance. At typical activity levels, the full plan allowance applies. Higher sustained activity can lower the allowance until earlier attempts leave the 7-day window.

Please refer docs for additional details.

Review details

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: 740be0fb-2a8e-4569-9f66-e1d75db9cacc

📥 Commits

Reviewing files that changed from the base of the PR and between a1addff and a10600f.

📒 Files selected for processing (6)

• benchmarks/Kevlar.Benchmarks/TimeoutBenchmarks.cs
• docs/docs/strategies/timeout.md
• src/Kevlar/PublicAPI.Unshipped.txt
• src/Kevlar/Strategies/Timeout/TimeoutOptions.cs
• src/Kevlar/Strategies/Timeout/TimeoutStrategy.cs
• tests/Kevlar.Tests/TimeoutDynamicOptionsTests.cs

---

_{Comment @coderabbitai help to get the list of available commands.}