Open Loop: rename rules -> loops in the engine

[suleimansh]

Part of #204 (first slice).

Rename the engine's 'rules' vocabulary to 'loops'. A loop is a meta prompt ("if code is ugly, spawn a cleanup agent"), so the user-facing unit is a loop even though it is powered by rule logic underneath.

Scope:

• Rename defaultLoopRules() and the rules type/params to loops.
• Keep the orchestration guards (infinite-loop / max-duration) internal to the framework; those are not an Open Loop concern.
• No behavior change, vocabulary only.

Blocks the bundle unit below.