feat(family): the adoption ledger - assessment, the conflict order, owed->task, recheck, the adoption matrix (milestone 463 step 4, #4990)

- services/family_adoption.py: assess one project against one canon idea by
  the four outcomes in order (exempt, variant, adopted, owed). Every outcome
  needs a reason and adopted needs evidence. The engine records the precedents
  itself: this idea's answers elsewhere, and this project's answers to the
  nearest ideas. The same answer given twice records nothing.
- owed files a task in the OWING project, tagged to the System matching the
  idea's canonical area, naming the gap and the reference for that project's
  language. The task follows the answer: adopted closes it, exempt or variant
  cancels it, owed again reopens it. Each move is logged on the task.
- the conflict order is enforced: every ground above the deciding one must
  say why it did not decide. The losing side is folded into the idea's note as
  a trap, an alternative or a condition branch, the version moves, and both
  rows are answered against the revision.
- recheck is derived (row version != idea version). family.revise moves the
  version when substance changes. undo covers a project's latest answer too.
- set_family_references names the reference implementations.
- MCP: get/list/assess adoption, resolve_family_conflict, revise_family_idea,
  set_family_references. Web: GET /api/family/matrix.
- UI: an adoption matrix on /family (platform filter, cell detail with reason,
  recheck and owed-task link) and the same matrix narrowed to one project on
  its Family tab. The decision log now reads project-level decisions.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/scribe/mcp/server.py

@@ -163,9 +163,11 @@ _READ_ONLY_TOOLS = frozenset({
     # The platform catalog and a project's answers (milestone 463). A pure
     # read; set_project_platforms is the write.
     "list_platforms",
-    # Family canon (milestone 463): ideas, one idea with its precedents, and
-    # the decision log. Reads of records the caller can read.
+    # Family canon (milestone 463): ideas, one idea with its precedents, the
+    # decision log, and the adoption ledger. Reads of records the caller can
+    # read.
     "list_family_ideas", "get_family_idea", "list_family_decisions",
+    "get_family_adoption", "list_family_adoptions",
     # The pass over the corpus and its queue (milestone 458 step 7): which
     # rules are unjudged and which proposals wait. Reads of the caller's own
     # rules, as list_rules is.
@@ -193,6 +195,9 @@ _WRITE_TOOLS = frozenset({
     # family canon — the promotion engine
     "propose_family_idea", "promote_family_idea", "retire_family_idea",
     "undo_family_decision",
+    # family canon — the adoption ledger
+    "revise_family_idea", "assess_family_adoption", "resolve_family_conflict",
+    "set_family_references",
     "bind_repo", "unbind_repo",
     # snippets, processes, the shape ledger
     "create_snippet", "update_snippet", "delete_snippet", "verify_snippet",