Add docs/v0.2-scope.md — canonical schema and audit contract proposal

Reviewable spec for v0.2, not a roadmap. Ten sections covering:

- Positioning as a proposed canonical schema for IB slide primitives,
  not a competing renderer.
- Canonical core of 5 templates (financial_summary, trading_comps,
  transaction_comps, sensitivity, operating_metrics). 3 ship today,
  1 aliased (dual_chart -> operating_metrics), 1 new.
- Four handshake files: spec.json, provenance.json, deck.exceptions.json,
  audit.report.json, with full JSON examples.
- source_refs schema, import_config schema, command contracts for
  /ib-import-excel, /ib-render, /ib-audit.
- First 10 audit checks ordered by operational value, with explicit
  severity (FAIL/WARN/INFO) and rationale.
- Per-command acceptance criteria, explicit non-goals, known limitations,
  and open questions for the Claude team.

v0.2 drops /ib-refresh as premature and cuts auto-inference of mappings
to v0.3. Stale-recalc and multi-workbook audit are named as honest
limitations. The proposal is that Anthropic could adopt the primitives
internally; this repo would become the reference implementation.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: gorajin