Python: Fix type hint for Case and Default

[cecheta]

Motivation and Context

Closes #3974

Description

Case and Default should accept SupportsAgentRun as target, and should not accept str as it throws an error here.

Contribution Checklist

• The code builds clean without any errors or warnings
• The PR follows the Contribution Guidelines
• All unit tests pass, and I have added new tests where possible
• Is this a breaking change? If yes, add "[BREAKING]" prefix to the title of the PR.

[markwallace-microsoft]

Python Test Coverage Report •

File	Stmts	Miss	Cover	Missing
packages/core/agent_framework
_types.py	998	92	90%	49, 58–59, 113, 118, 137, 139, 143, 147, 149, 151, 153, 171, 175, 201, 223, 228, 233, 237, 263, 267, 613–614, 985, 1047, 1064, 1082, 1087, 1105, 1115, 1132–1133, 1135, 1153–1154, 1156, 1163–1164, 1166, 1201, 1212–1213, 1215, 1253, 1480, 1532, 1623–1628, 1650, 1655, 1821, 1833, 2076, 2085, 2106, 2201, 2426, 2633, 2703, 2715, 2722, 2733, 2931–2933, 2936–2938, 2942, 2947, 2951, 3035–3037, 3066, 3120, 3124–3126, 3128, 3139–3140, 3143–3147, 3153
packages/core/agent_framework/_workflows
_edge.py	229	28	87%	47, 69–70, 72, 167, 197, 446–447, 452, 456–461, 463–465, 581, 695, 702–704, 751, 779, 805, 859, 873
TOTAL	20564	3243	84%

Python Unit Test Overview

Tests	Skipped	Failures	Errors	Time
3955	225 💤	0 ❌	0 🔥	1m 12s ⏱️

[Copilot]

Pull request overview

This PR fixes the type hints for Case and Default classes in the workflow package to correctly accept SupportsAgentRun instances as targets, resolving issue #3974.

Changes:

• Updated Case.target and Default.target type hints from Executor | str to Executor | SupportsAgentRun
• Added import for SupportsAgentRun from ._agents module
• Reformatted tools type annotation in _types.py from multi-line to single-line

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
python/packages/core/agent_framework/_workflows/_edge.py	Fixed type hints for Case and Default target parameter to accept SupportsAgentRun instead of str, and added required import
python/packages/core/agent_framework/_types.py	Reformatted tools type annotation from multi-line to single-line