Implement ExecPlan

Execute the pending execution plan located at .agent/execplan-pending.md in the current repository OR if the user mentioned another execplan at a different file path, implement that one.

Do not treat the ExecPlan as a blind checklist. Use it as the implementation contract for delivering the intended behavior and the intended simplification of the system.

Ousterhout lens

Use John Ousterhout's design philosophy when the plan leaves room for judgment:

• prefer deep modules over shallow wrappers
• prefer interfaces that hide sequencing and policy
• prefer fewer concepts, fewer knobs, and fewer special cases
• prefer simple mental models over clever decomposition
• prefer concentrating complexity behind a stable boundary over spreading it across call sites

Treat these as the main forms of complexity: