Add agent-v1 shell command attribution

[Siddhant-K-code]

Summary

• Add pre_shell_command and post_shell_command payloads to the agent-v1 preset
• Map those payloads onto the existing PreBashCall/PostBashCall stat-diff flow
• Add parser/unit coverage and an integration scenario for shell-generated file changes

Fixes #1313.

Validation

Run from the repo root on this branch:

task fmt
task lint
task test TEST_FILTER=agent_v1

Expected outcomes:

• task fmt exits cleanly with no rustfmt diffs.
• task lint exits cleanly with no clippy/lint failures.
• task test TEST_FILTER=agent_v1 passes the agent-v1 parser tests and the shell-command e2e regression.
• test_agent_v1_shell_command_e2e_attribution creates a shell-generated line, commits it, and verifies the committed/blame view treats that line as AI-authored.

Additional whitespace check:

git diff --check origin/main..siddhant/1313-agent-v1-shell-attribution

Expected outcome: no output and exit code 0.

Docs

No docs change needed. This is a hook payload compatibility addition for the agent-v1 integration and is covered by parser and integration tests.

Notes

PR for focused review and CI validation.

[devin-ai-integration]

✅ Devin Review: No Issues Found

Devin Review analyzed this PR and found no bugs or issues to report.