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>

examples/phase-001/manifest.json

@@ -0,0 +1,32 @@
+{
+  "framework": "TRF-0.1",
+  "license": "TRSL-0.1",
+  "phase": {
+    "id": "trsl:phase:example-001",
+    "milestone_release": {
+      "name": "release-1.0",
+      "source_revision": "abc123",
+      "artifact_sha256": "44cd1493bd179c1207c7025c1372cdad89aac114e151db27aba2bdf3d55c688a"
+    },
+    "initial_target": {
+      "amount": 100000,
+      "currency": "USD"
+    },
+    "target_basis": {
+      "estimated_effort_days": 1,
+      "daily_rate": 1000,
+      "approved_direct_costs": 0,
+      "target_multiple": 100
+    },
+    "future_license": "MIT",
+    "degeneration_policy": "trsl:policy:linear-longstop-v0@1.0",
+    "longstop_at": "2031-08-01T00:00:00Z",
+    "ledger": "examples/phase-001/ledger.json"
+  },
+  "extensions": [
+    "trsl:extension:development-license@1.0",
+    "trsl:extension:cost-plus-operations@1.0",
+    "trsl:extension:phase-sponsorship@1.0",
+    "trsl:extension:service-with-development-allocation@1.0"
+  ]
+}