Implement sponsor compliance check using stance-aware scorer

[EightRice]

Goal

Sponsors automatically score whether their dependents' work aligns with the sponsor's charter, using the same stance-aware scoring as the alignment pricing function.

Current state

nodes/common/sponsor_agent_manager.py:check_alignment (lines 239–275) computes alignment via keyword overlap with a TODO marker for actual embeddings (line 262). The score is recommendation-only; it doesn't influence reward distribution or sponsor-side budget gating.

Scope

• Replace the keyword-overlap stub with calls into the stance-aware scorer (see related alignment-pricing issue).
• Define the trigger: per-heartbeat? per-dependent-action? per-budget-allocation? Pick one, document it.
• Define the consequence: pure advisory (sponsor sees a score), soft (warning surfaced to user), or hard (budget pull-back). Default: advisory.
• On-chain hook: optional. If hard enforcement is chosen, wire into RPB's training reward distribution.

Acceptance

• A test where a dependent agent operates outside its sponsor's charter shows a meaningfully lower compliance score than an aligned dependent.
• Score appears in the snapshot under each sponsor's view of its dependents.

Depends on

• Stance-aware alignment scorer (separate issue) — this issue should not duplicate that infrastructure.