CIC for ReconciliationModule + migration docs

[Polichinel]

Epic: #31 · Depends on: #36

Background

Repo convention (ADR-006, docs/CICs/) requires a Class Intent Contract for non-trivial / orchestration classes. The slice-1 review flagged that the orchestration class (#36) will need one.

Work

• Write docs/CICs/ReconciliationModule.md following docs/CICs/cic_template.md: Purpose, Responsibility Boundary, Invariants, Explicit Non-Responsibilities (does not embed geography; does not change the algorithm; does not fetch the mapping), and Failure Semantics.
• Update the migration notes / risk register: reconciliation now lives here, frames-native, parity-proven; cross-link C-37 (the deferred algorithm upgrade) and views-reporting#72.

Acceptance criteria

• CIC follows the template and matches the actual ReconciliationModule orchestration (numpy-native; drop wandb + multiprocessing) #36 behaviour (no aspirational claims — cf. Cluster F drift in this repo's history).
• Migration status documented; C-37 and #72 cross-linked.

Validation

• docs/validate_docs.sh (if present) passes; manual read-through against the code.