docs(6209): twelve more test files say which behaviour they pin

shape ledger, MCP projects/search/rulebooks tools, backup, chunking,
plugin context, derived mirror, rule band, shape form gate, plugin
version mint and note usage tests drop issue, milestone and rule numbers,
dates and one-install figures from docstrings, comments and messages.
Three shape-form-gate test names that told the discovery story now name
the property: a registry module's helpers are not service functions, the
divergence gate silences only a family contradiction, and callable helpers
beside a callable canon still prompt. The rulebook tool-count comment that
logged each milestone's additions is replaced by the reason it is a count.

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

tests/test_shape_form_gate.py

@@ -1,16 +1,15 @@
-"""A canon may only be urged on a shape that could plausibly BE it (#4204).
+"""A canon may only be urged on a shape that could plausibly BE it.
 
-WHAT WAS WRONG. `dominant_canon` is a base rate: it answers "what is most
-common in this directory" and never "is this that". With `kind` carrying only
-`css | sym`, a frozen dataclass, a module constant, a sync predicate, a class
-and an async service function were all siblings, so the prior was the entire
-argument — it told a registry module of pure helpers to build from the
-`async_session` service canon. Upstream, the auto-stamp had no resemblance
-floor at all (`elif sid in resembles`), so 0.69 asserted as confidently as
-0.95, and one payload-level score was applied to every symbol in the file.
+WHY. `dominant_canon` is a base rate: it answers "what is most common in this
+directory" and never "is this that". With `kind` carrying only `css | sym`, a
+frozen dataclass, a module constant, a sync predicate, a class and an async
+service function are all siblings, so the prior is the entire argument — it
+would tell a registry module of pure helpers to build from an
+`async_session` service canon. An auto-stamp without a resemblance floor
+asserts 0.69 as confidently as 0.95.
 
 The two halves compound: loose stamping manufactures the density that the
-divergence check then reads as authority. Both are fixed by the same
+divergence check then reads as authority. Both are held by the same
 primitive, and it is tested here on REAL signatures taken from the ledger —
 Python, Go, TypeScript and Vue — rather than invented ones, because a
 classifier that only works on the examples its author imagined is the failure
@@ -75,9 +74,9 @@ def test_css_is_its_own_form_regardless_of_signature() -> None:
     assert shape_form("", "css") == "css"
 
 
-def test_the_five_shapes_that_started_this_are_not_service_functions() -> None:
-    """The concrete case. #2860 is an `async def` service unit; none of these
-    is one, and all five were told to build from it."""
+def test_a_registry_modules_helpers_are_not_service_functions() -> None:
+    """The concrete case. The canon is an `async def` service unit; none of
+    these is one."""
     canon = shape_form("async def create_note(user_id: int, ...):", "sym")
     assert canon == "async-fn"
     for sig in (
@@ -90,27 +89,25 @@ def test_the_five_shapes_that_started_this_are_not_service_functions() -> None:
         assert not forms_agree(shape_form(sig, "sym"), canon), sig
 
 
-def test_how_many_of_the_five_the_divergence_gate_actually_silences() -> None:
+def test_the_divergence_gate_silences_only_a_family_contradiction() -> None:
     """HONEST ACCOUNTING, and it is deliberately an assertion rather than a
     comment so it fails the day the answer changes.
 
     Divergence gates at FAMILY level and only on contradiction, because a form
     mismatch is the PREMISE of a divergence prompt, not an objection to it —
-    see `shape_family`. So of #4204's five false prompts this silences one:
-    `Point` is a type and the canon is a callable. The four `def` helpers are
-    callables like the canon and still ask.
+    see `shape_family`. So of these five this silences one: `Point` is a type
+    and the canon is a callable. The four `def` helpers are callables like the
+    canon and still ask.
 
     That is not a shortcoming of the gate, it is the limit of the signature:
-    at this level those four are indistinguishable from #2793's acceptance
-    case, where a sync `confirmDanger` beside an async confirm helper SHOULD
-    be flagged.
+    at this level those four are indistinguishable from the divergence
+    readout's acceptance case, where a sync `confirmDanger` beside an async
+    confirm helper SHOULD be flagged.
 
-    CORRECTED 2026-09-21 (#4208). This used to say separating them needs
-    "widen `kind` or a comparison of meaning", offering the two as
-    alternatives. Widening `kind` does not separate them: it buys the silence
-    by bucketing `fn` apart from `async-fn`, which takes the async canon out
-    of a sync candidate's denominator and silences #2793's acceptance case by
-    the identical mechanism, one layer down. Whatever separates these four
+    Widening `kind` does not separate them: it buys the silence by bucketing
+    `fn` apart from `async-fn`, which takes the async canon out of a sync
+    candidate's denominator and silences the acceptance case by the identical
+    mechanism, one layer down. Whatever separates these four
     has to distinguish a helper that does the canon's JOB from one that does
     not, and no signature carries that. A comparison of meaning is the only
     lever, not one of two."""
@@ -130,10 +127,10 @@ def test_how_many_of_the_five_the_divergence_gate_actually_silences() -> None:
 
 
 def test_a_sync_function_beside_an_async_canon_is_still_a_fair_question() -> None:
-    """#2793's acceptance case, which the first version of this change broke:
-    gating divergence on `forms_agree` silenced a hand-rolled sync confirm in
-    a directory where an async confirm helper is canon — the exact prompt the
-    milestone exists to produce."""
+    """The divergence readout's acceptance case: gating divergence on
+    `forms_agree` would silence a hand-rolled sync confirm in a directory
+    where an async confirm helper is canon — the exact prompt the readout
+    exists to produce."""
     canon = shape_form("async function onTrash() {", "sym")
     mine = shape_form("function confirmDanger() {", "sym")
     assert canon == "async-fn" and mine == "fn"
@@ -185,8 +182,8 @@ def test_a_canon_whose_instances_agree_asserts_that_form() -> None:
 
 
 def test_a_canon_whose_instances_disagree_asserts_nothing() -> None:
-    """Portal's #3283 exactly: one snippet recorded as canon for a class, a
-    plain def, an async def and a dozen tests. That spread is the SYMPTOM of
+    """One snippet recorded as canon for a class, a plain def, an async def
+    and a dozen tests. That spread is the SYMPTOM of
     loose stamping, so reading it as "no opinion" makes the two fixes
     cooperate — a poisoned canon falls silent instead of flagging others."""
     rows = [_Row("class A:"), _Row("def b():"), _Row("async def c():")]
@@ -334,7 +331,7 @@ def test_the_resemblance_floor_is_above_the_retrieval_floors() -> None:
     assert _RESEMBLE_MIN >= 0.80
 
 
-# ── The denominator, not the gate (#4208) ─────────────────────────────────
+# ── The denominator, not the gate ─────────────────────────────────────────
 #
 # `dominant_canon` is a base rate, and a base rate is only a statement about
 # something if its denominator is a population somebody asked a question
@@ -369,7 +366,7 @@ def test_a_callable_is_not_counted_against_a_dataclass() -> None:
 
 
 def test_the_async_canon_stays_in_a_sync_candidates_denominator() -> None:
-    """THE ACCEPTANCE CASE OF #2793, and the reason this narrows by family
+    """THE DIVERGENCE READOUT'S ACCEPTANCE CASE, and the reason this narrows by family
     rather than by form.
 
     A hand-rolled sync `confirmDanger` in a directory where an async confirm
@@ -421,13 +418,13 @@ def test_a_family_passed_where_a_form_belongs_would_be_a_silent_no_op() -> None:
     assert by_form != by_family
 
 
-def test_the_four_survivors_still_prompt() -> None:
+def test_callable_helpers_beside_a_callable_canon_still_prompt() -> None:
     """HONEST ACCOUNTING, matching the sibling test above.
 
-    The narrowed denominator does not silence #4204's four `def` helpers, and
-    was never going to: they are callables, the canon is a callable, so
-    nothing is excluded from their count. What changes is that the count is
-    now over comparable things. Asserted so the claim cannot quietly rot into
+    The narrowed denominator does not silence the four `def` helpers, and
+    cannot: they are callables, the canon is a callable, so nothing is
+    excluded from their count. What it buys is that the count is over
+    comparable things. Asserted so the claim cannot quietly rot into
     "this fixed it".
     """
     rows = [_Row(SERVICE) for _ in range(6)] + [_Row("class Point:", snippet_id=9)]