Remove max_repair_rounds parameter and its callers

[zhongkaifu]

Motivation

• Remove the external max_repair_rounds knob from CLI, helper and web entrypoints to simplify the planner API and avoid exposing an extra tuning parameter.
• Treat repair iteration limits as an internal implementation detail rather than a caller-provided argument.

Description

• Drop the --max-repair-rounds CLI argument and stop passing max_repair_rounds into update_workflow_with_two_pass in update_workflow.py.
• Remove the max_repair_rounds argument from the plan_workflow_with_two_pass call in the interactive helper in build_workflow.py.
• Stop passing max_repair_rounds from the web API dispatch logic in webapp/server.py.
• Update the test tests/test_update_workflow_planner.py to stop supplying the removed argument, and adjust the README wording to refer to repair loop behavior without referencing the removed parameter.

Testing

• The unit test tests/test_update_workflow_planner.py was updated to remove the now-unused max_repair_rounds argument; no automated test suite was executed as part of this change.
• No automated tests were run in the rollout (no failures reported).

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Codex Task