docs(obligations): address CodeRabbit review on #176

- P-025: tag the protocol-verbs fence as text (MD040; the C# fence was
  already tagged)
- __main__: de-OWN050-ify the cmd_ownir docstring and the advisory comment
  block — the band now carries OBL005 too
- diagnostics: EXPLANATIONS for the maybe-siblings OBL002/OBL004, mirroring
  OBL001/OBL003 so ownlang explain answers all four symmetrically

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NXzqX7Qwn5QzBLGVCATdgm

Author: claude

docs/proposals/P-025-obligation-protocols.md

@@ -47,7 +47,7 @@ subscription-leak epicenter).
 
 The same three verbs cover the whole family:
 
-```
+```text
 IsLoaded=false            must become true      before PropertyChanged(Document)
 _suppressNotifications    must be restored      before return/throw
 BeginUpdate               must meet EndUpdate   before Refresh / method exit

ownlang/__main__.py

@@ -307,7 +307,7 @@ def cmd_ownir(path: str, fmt: str = "human", severity: str = "error",
     selects the surface: human (CLI), github (CI annotations), msbuild (VS),
     sarif (SARIF 2.1.0 log);
     `severity` picks how the host shows them (error/warning); `verbosity` is
-    `quiet` (errors only — hide the advisory OWN050 notes), `normal` (default), or
+    `quiet` (errors only — hide the advisory notes), `normal` (default), or
     `verbose` (also print a per-code breakdown)."""
     from .ownir import OwnIRError, build_sarif, check_facts, load, render_finding
     try:
@@ -321,9 +321,9 @@ def cmd_ownir(path: str, fmt: str = "human", severity: str = "error",
     # pollute that stream.
     machine = fmt in {"github", "msbuild", "sarif"}
     summary_to = sys.stderr if machine else sys.stdout
-    # OWN050 "leakage analysis skipped" notes are advisory (P-014 Tier A): always
-    # shown as warnings regardless of --severity, and never affect the exit code —
-    # they are coverage notes ("we could not check this"), not verdicts.
+    # Advisory findings (OWN050 "leakage analysis skipped", OBL005 "dead protocol
+    # rule") are always shown as warnings regardless of --severity, and never
+    # affect the exit code — they are coverage/hygiene notes, not verdicts.
     leaks = [f for f in findings if not f.advisory]
     notes = [f for f in findings if f.advisory]
     shown = leaks if verbosity == "quiet" else findings

ownlang/diagnostics.py

@@ -197,6 +197,14 @@ class Severity(Enum):
         "the notification), or — if that notification is genuinely safe while open — add it to "
         "the protocol's `allow` list."
     ),
+    "OBL002": (
+        "Like OBL001, but the obligation is open on only *some* paths that reach the barrier — "
+        "whether the notification publishes a broken object depends on the branch taken (the "
+        "same definite/maybe split as OWN002 vs OWN009).\n"
+        "Fix: close the obligation on every path before the barrier (or on none — make the "
+        "state unambiguous), or add the call to the protocol's `allow` list if it is genuinely "
+        "safe while open."
+    ),
     "OBL003": (
         "A project-declared obligation is opened but not closed before the method exits "
         "(return / throw / falling off the end) on every path — the object is left in its "
@@ -205,6 +213,13 @@ class Severity(Enum):
         "forever when `Load()` throws.\n"
         "Fix: close in a `finally`, or on every early-return path."
     ),
+    "OBL004": (
+        "Like OBL003, but the obligation is left open on only *some* exit paths — whether the "
+        "object stays broken depends on the branch taken (typically an early return or a "
+        "may-throw call before the close).\n"
+        "Fix: close on every exit path — a `finally` covers the throw paths; move the close "
+        "above the early returns."
+    ),
     "OBL005": (
         "Advisory, not a verdict: a protocol's `scope.methods` matched none of the methods the "
         "frontend reported events for — the rule is dead (usually a typo'd or renamed method "