feat(sdk-python): expose execution context via app.ctx property

[AbirAbbas]

Summary

• Add ctx property to Agent class for direct access to execution context during reasoner/skill execution
• Returns None outside of active execution to prevent accidental use of stale context
• Fix integration test fixtures to support current monorepo structure

Motivation

Previously, accessing the execution context required importing a separate function:

from agentfield.execution_context import get_current_context

@app.reasoner()
async def handle_ticket(ticket_id: str):
    ctx = get_current_context()
    await app.memory.workflow(ctx.workflow_id).set("status", "processing")

Now users can access it directly via app.ctx:

@app.reasoner()
async def handle_ticket(ticket_id: str):
    await app.memory.workflow(app.ctx.workflow_id).set("status", "processing")

Behavior

Scenario	app.ctx returns
Inside reasoner/skill (via HTTP request)	Valid ExecutionContext
Inside nested agent call	Valid child ExecutionContext
Outside any execution	None
After request completes	None

This matches the behavior of app.memory which also returns None outside of execution.

Test plan

• Unit tests verify ctx returns None outside execution
• Unit tests verify ctx returns context during execution
• Unit tests verify ctx ignores unregistered contexts
• Integration test verifies end-to-end behavior (requires FTS5-enabled SQLite)
• All 371 existing tests pass

🤖 Generated with Claude Code