Feat/v0.9.0 task coordination

[ikelaiah]

What does this PR do?

Prepares the v0.9.0 release by adding observable task coordination while preserving compatibility with existing v0.8.x programs.

Key changes:

• Adds ThreadPool.Tasks with observable task handles, lifecycle states, timed and indefinite waiting, error reporting, and pending-task cancellation.
• Adds task batches for waiting, progress counts, failure inspection, and group cancellation.
• Adds efficient chunked SubmitRange processing.
• Adds Submit and TrySubmit support to both Simple and Producer-Consumer pools.
• Preserves the existing IThreadPool interface and GUID for v0.8 compatibility.
• Adds deadlock protection for unsafe self-waiting and nested bounded ranges.
• Adds task coordination tests, compatibility tests, benchmarks, API documentation, release notes, and real-world examples.
• Adds PowerShell and POSIX scripts that build all examples into example-bin/.
• Updates the Lazarus package and documentation for v0.9.0.

Local verification completed on Windows:

• 81 tests passed with no failures or memory leaks.
• Package and Release benchmark builds passed.
• Benchmark smoke test passed.
• All 15 examples built successfully.

Related issue

None.

Type of change

• 🐛 Bug fix
• ✨ New feature
• 📝 Documentation / examples
• 🔧 Refactor / internal change

Checklist

• Tests pass locally (lazbuild tests/TestRunner.lpi then run TestRunner)
• Added/updated tests where it makes sense
• Updated CHANGELOG.md
• Updated docs in docs/ if behavior or API changed
• New units use {$mode objfpc}{$H+}{$J-} and filenames match unit casing