Implement TREV-WP-0002 Stage 0 foundation: schemas, pure fold, golden Phase

Delivers the offline runnable specification foundation for the Trust Layer
(TSD §3-§6), not a hosted Trust Service:

- JSON Schemas for Phase Manifest, Ledger Entry, Extension Contract, and
  Conversion Attestation, encoding the Stage 0 working defaults (Q3 future
  license enum, Q6 single-currency Phases, Q8 required longstop_at).
- src/target_revenue: pure Outstanding Target fold, SHA-256 hash-chain
  verification, Ed25519 signing helpers, extension conformance checks
  (including a core-term-redefinition heuristic), and conversion detection
  that never requires an attestation document to determine conversion status.
- examples/phase-001: golden Phase package matching the concept doc's
  worked example, generated via scripts/generate_golden_phase.py so the
  hash chain is computed by the library itself, not hand-typed.
- 32 passing pytest tests covering manifest/ledger/extension conformance,
  tamper/reorder detection, and the full lifecycle fold to conversion.
- docs/adr/ADR-0001: proposed (not accepted) Stage 0 stack choice, per the
  WP-0002-T01 human-accept gate — implementation proceeded against the
  proposal as the workplan note permits, but the task stays open.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

pyproject.toml

@@ -0,0 +1,26 @@
+[build-system]
+requires = ["hatchling"]
+build-backend = "hatchling.build"
+
+[project]
+name = "target-revenue"
+version = "0.1.0"
+description = "Stage 0 schemas, pure Outstanding Target fold, and offline validators for the Target Revenue Framework (TRF)."
+readme = "README.md"
+requires-python = ">=3.11"
+license = { text = "MIT-0" }
+dependencies = [
+    "jsonschema>=4.21",
+    "cryptography>=42.0",
+]
+
+[project.optional-dependencies]
+dev = [
+    "pytest>=8.0",
+]
+
+[tool.hatch.build.targets.wheel]
+packages = ["src/target_revenue"]
+
+[tool.pytest.ini_options]
+testpaths = ["tests"]