Detect and attribute file modifications made by subagents

[jcleira]

Description

Partio currently captures file changes made by the primary agent session. Extend session tracking to also detect and attribute file modifications made by subagents spawned during a session (e.g., Claude Code spawning sub-agents via the Agent tool). Changes made by subagents should be included in the parent session's checkpoint with appropriate attribution.

Source

• Origin: fix: subagent file modifications invisible to checkpoint detection (ENT-297) entireio/cli#323 (changelog 0.4.5)
• Detected from: entireio-cli

Target Repos

• cli

Acceptance Criteria

• File modifications from subagent processes are detected and included in the parent session checkpoint
• Subagent contributions are attributed distinctly (e.g., tagged in metadata) from primary agent changes
• No duplicate attribution when the primary agent and subagent modify the same file
• Existing checkpoint attribution tests pass; add test for subagent scenario

Context Hints

• cli/internal/session/
• cli/internal/checkpoint/
• cli/internal/agent/

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[jcleira]

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[jcleira]

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PRs created:

• [minion] Detect and attribute file modifications made by subagents cli#16