Give each role its own view of the transcript (M1.2)

A model no longer reads another role's turns as its own (#78). The log
stays one record per work item; what a role is shown is projected from
it by Transcript.view() (views.py), which the planner, executor and
helper now build their context from:

- own events unchanged;
- operator messages labelled with their channel, e.g.
  [operator, Matrix] or [operator, comment on PR #165];
- orchestrator facts (a new `fact` event) as [orchestrator] statements;
- the executor sees a helper's handback as [helper report], not its turns;
- a helper sees the approved plan and the executor's milestone work as
  one-line narration;
- the planner sees no other role's work at all.

The orchestrator now writes facts at the points the models must know
about: work item opened, plan approved or rejected, milestone started,
finished or stopped, published (with PR number and URL) or not, review
comment answered, next milestone, task completed or abandoned.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PPQ14L3LikyefCMFBqEbKE

nisse-dev/tests/test_dump.py

@@ -1,7 +1,7 @@
 import io
 from pathlib import Path
 
-from nisse_dev.canonical import PlanSubmitted, ToolCall, ToolResult, UserMessage
+from nisse_dev.canonical import Fact, PlanSubmitted, ToolCall, ToolResult, UserMessage
 from nisse_dev.dump import main, render
 from nisse_dev.oplog import OpLog
 from nisse_dev.state import StateStore
@@ -55,6 +55,15 @@ def test_full_shows_long_texts_whole(tmp_path: Path) -> None:
     assert "x" * 500 in render(db, full=True)
 
 
+def test_facts_are_shown_as_the_orchestrators(tmp_path: Path) -> None:
+    db = tmp_path / "state.db"
+    store_with_a_run(db)
+    store = StateStore(db, oplog=OpLog("nisse-dev", io.StringIO()))
+    store.transcript("demo-1", "orchestrator").append(Fact(text="PR #3 opened"))
+    store.close()
+    assert "[demo-1/orchestrator] FACT: PR #3 opened" in render(db)
+
+
 def test_the_dump_never_writes_to_the_store(tmp_path: Path) -> None:
     db = tmp_path / "state.db"
     store_with_a_run(db)