Keep task graph off the default status hot path

[huangruiteng]

Summary

• keep task_graph_projection_v0 off default loopx status output to preserve the dashboard status interface budget
• add loopx status --include-task-graph for callers that explicitly need the optional graph
• keep full review packets graph-capable while handoff-only packets remain compact
• document the hot/cold path split and assert the default hot path omits the graph

Validation

• python3 examples/hot-path-interface-budget-smoke.py
• python3 examples/task-graph-projection-fixture-smoke.py
• python3 examples/review-packet-cli-smoke.py
• python3 -m py_compile loopx/status.py loopx/cli_commands/status.py
• python3 examples/status-markdown-smoke.py
• python3 examples/goal-channel-status-export-smoke.py
• loopx check --scan-path loopx/status.py --scan-path loopx/cli_commands/status.py --scan-path examples/hot-path-interface-budget-smoke.py --scan-path docs/status-data-contract.md --scan-path docs/reference/protocols/task-graph-projection-v0.md
• git diff --check

Focused result: dashboard_status_json is now 17634/18000 in the hot-path smoke; default source CLI omits task_graph_projection, while --include-task-graph includes it.

[huangruiteng]

Self-review: this PR fixes the dashboard status hot-path budget regression by moving optional task graph projection behind an explicit cold-path flag. The root cause was not the todo lanes themselves, but always attaching task_graph_projection_v0 to default status rows after the graph became stable. Focused validation passed, with dashboard_status_json now at 17634/18000 in examples/hot-path-interface-budget-smoke.py; source CLI default omits the graph, and --include-task-graph includes it. I do not recommend self-merging this without review because it changes core status CLI/runtime behavior, even though the diff is narrow.

[huangruiteng]

Findings: none from this review pass.

Open questions / assumptions: I treated this as a status hot-path budget repair that moves task_graph_projection behind explicit --include-task-graph / full review-packet paths while preserving the cold-path graph for consumers that ask for it.

Validation performed:

• python3 examples/hot-path-interface-budget-smoke.py passed on the PR head.

Merge decision: hold for normal reviewer/branch-protection flow; no blocker found in the diff plus focused hot-path smoke.