Remove streaming dependencies and move to StreamCallbacks.jl

[Sixzero]

This PR removes all streaming-related dependencies and implementation from PromptingTools.jl and moves them to the dedicated StreamCallbacks.jl package.

Summary of changes

• streaming.jl file now is just an interface other packages can use, to develop any kind of streaming callback based IO based or with any kind of backend, HTTP.jl libCurl, EasyCurl etc.

Changes Made

Removed Dependencies:

• Removed StreamCallbacks from direct dependencies in Project.toml
• Cleaned up streaming-related imports from main module

Refactored Streaming Interface:

• Replaced full streaming implementation with minimal interface in src/streaming.jl
• Added abstract AbstractStreamCallback type for extensibility
• Kept essential interface methods (configure_callback!, streamed_request!) as stubs

Updated Documentation:

• Updated docstrings in aigenerate functions across all schemas (OpenAI, Anthropic, Ollama)
• Added clear instructions for users to using StreamCallbacks for streaming functionality
• Updated examples to show proper StreamCallbacks.jl usage

Test Cleanup:

• Removed test/streaming.jl as streaming tests are now in StreamCallbacks.jl
• Updated test runner to exclude streaming tests

Benefits

1. Lighter Core Package: PromptingTools.jl is now lighter without heavy streaming dependencies
2. Focused Development: Streaming functionality can evolve independently in StreamCallbacks.jl
3. Better Separation of Concerns: Core prompting vs streaming concerns are properly separated
4. Maintained Compatibility: Existing streaming code will work with using StreamCallbacks

Migration for Users

Users who use streaming features need to add one line:

using StreamCallbacks  # Add this line
# All existing streaming code works unchanged

Breaking Changes

• Direct access to streaming types (e.g., PT.StreamCallback) now requires using StreamCallbacks
• No functional breaking changes - all streaming features remain available through StreamCallbacks.jl

This change improves the package architecture while maintaining full backward compatibility for end users.

[codecov]

Codecov Report

❌ Patch coverage is 0% with 4 lines in your changes missing coverage. Please review.
⚠️ Please upload report for BASE (main@f9304d8). Learn more about missing BASE report.
⚠️ Report is 21 commits behind head on main.

Files with missing lines	Patch %	Lines
src/streaming.jl	0.00%	4 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #307   +/-   ##
=======================================
  Coverage        ?   92.62%           
=======================================
  Files           ?       37           
  Lines           ?     3242           
  Branches        ?        0           
=======================================
  Hits            ?     3003           
  Misses          ?      239           
  Partials        ?        0           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.