Implement WP-0015-T01/T04/T06: Phase provenance schema + ledger UI

Schema: phase.milestone_release gains required repo_hub/repo_hub_uri/
repo_id/repo_name; phase gains optional base_phase_id. Backfilled the
golden phase-001 fixture (placeholder values, it's synthetic) and the
three real pilot-candidate manifests with actual Forgejo repo ids
confirmed live (net-kingdom=67, vergabe-teilnahme=62,
info-tech-canon=47, all coulomb/*).

Discovered along the way: the schema change alone would have broken
the existing Control Plane registration form, since nothing collected
the four new fields. Fixed inline rather than leaving it broken
between tasks -- this also completes T04's ledger UI change (drop the
hand-typed ledger input, auto-compute /phases/{id}/ledger, add a
drill-down reference link on phase_detail.html) since both changes
touch the same form/route.

Full suite: 94 passing offline (was 84), 158 passing with Docker
(was 146).

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

src/target_revenue/service/control_plane_app.py

@@ -198,26 +198,41 @@ def phase_new_submit(
     phase_id: str = Form(...),
     milestone_release_name: str = Form(...),
     source_revision: str = Form(...),
+    repo_hub: str = Form(...),
+    repo_hub_uri: str = Form(...),
+    repo_id: int = Form(...),
+    repo_name: str = Form(...),
+    base_phase_id: str = Form(""),
     initial_target_amount: float = Form(...),
     currency: str = Form(...),
     future_license: str = Form(...),
     degeneration_policy: str = Form(...),
     longstop_at: str = Form(...),
-    ledger_uri: str = Form(..., alias="ledger"),
 ):
     manifest = {
         "framework": "TRF-0.1",
         "license": "TRSL-0.1",
         "phase": {
             "id": phase_id,
-            "milestone_release": {"name": milestone_release_name, "source_revision": source_revision},
+            "milestone_release": {
+                "name": milestone_release_name,
+                "source_revision": source_revision,
+                "repo_hub": repo_hub,
+                "repo_hub_uri": repo_hub_uri,
+                "repo_id": repo_id,
+                "repo_name": repo_name,
+            },
             "initial_target": {"amount": initial_target_amount, "currency": currency},
             "future_license": future_license,
             "degeneration_policy": degeneration_policy,
             "longstop_at": longstop_at,
-            "ledger": ledger_uri,
+            # Auto-computed, never hand-typed (WP-0012-T04) -- this Trust
+            # Service instance is always the ledger's host in Stage 0.
+            "ledger": f"/phases/{phase_id}/ledger",
         },
     }
+    if base_phase_id:
+        manifest["phase"]["base_phase_id"] = base_phase_id
     try:
         control_plane.register_phase(conn, licensor, manifest)
     except (control_plane.ControlPlaneError, registry.RegistrationError) as exc:

src/target_revenue/service/control_plane_templates/phase_detail.html

@@ -6,6 +6,16 @@
 </wn-page-header>
 <p><wn-tag>{{ manifest.phase.id }}</wn-tag></p>
 
+<details style="margin-bottom:1rem;color:#888;font-size:0.9rem;">
+  <summary style="cursor:pointer;">Ledger reference (internal — not this Phase's ledger entries, see below)</summary>
+  <p>
+    Raw reference: <code>{{ manifest.phase.ledger }}</code>
+    {% if manifest.phase.ledger.startswith('/phases/') %}
+      &middot; <a href="{{ manifest.phase.ledger }}">view live JSON</a>
+    {% endif %}
+  </p>
+</details>
+
 <h3>Status</h3>
 <table class="wn-plain">
   <tr><td>Initial Target</td><td>{{ manifest.phase.initial_target.amount }} {{ manifest.phase.initial_target.currency }}</td></tr>

src/target_revenue/service/control_plane_templates/phase_new.html

@@ -19,6 +19,21 @@
   <wn-field-row label="Source revision">
     <wn-input name="source_revision" required></wn-input>
   </wn-field-row>
+  <wn-field-row label="Repo hub (stable Forgejo instance slug)">
+    <wn-input name="repo_hub" value="forgejo-coulomb" required></wn-input>
+  </wn-field-row>
+  <wn-field-row label="Repo hub URI">
+    <wn-input name="repo_hub_uri" value="https://forgejo.coulomb.social" required></wn-input>
+  </wn-field-row>
+  <wn-field-row label="Repo id (Forgejo's own numeric id)">
+    <wn-input type="number" name="repo_id" required></wn-input>
+  </wn-field-row>
+  <wn-field-row label="Repo name (owner/repo)">
+    <wn-input name="repo_name" required></wn-input>
+  </wn-field-row>
+  <wn-field-row label="Base Phase id (optional — only for a successive Phase)">
+    <wn-input name="base_phase_id"></wn-input>
+  </wn-field-row>
   <wn-field-row label="Initial Target amount">
     <wn-input type="number" step="0.01" name="initial_target_amount" required></wn-input>
   </wn-field-row>
@@ -37,9 +52,6 @@
   <wn-field-row label="Longstop date (ISO 8601)">
     <wn-input name="longstop_at" required></wn-input>
   </wn-field-row>
-  <wn-field-row label="Ledger URI (relative path or URL)">
-    <wn-input name="ledger" required></wn-input>
-  </wn-field-row>
   <wn-button type="submit" variant="primary">Register Phase</wn-button>
 </form>
 {% endblock %}