test: observe landblock worker joins

docs/reviews/2026-08-18-r3-test-truth-ledger.md

@@ -53,8 +53,8 @@ inventory refreshed for Batch L reports:
 | Constant-truth assertion methods / sites | 0 / 0 |
 | Reviewed syntactic self-comparison methods / sites | 4 / 5 |
 | Reviewed diagnostic methods | 57 |
-| Methods directly using `Thread.Sleep` / `Task.Delay` | 15 / 19 |
-| Cancellable-infinite-only / elapsed-time methods | 5 / 29 |
+| Methods directly using `Thread.Sleep` / `Task.Delay` | 15 / 17 |
+| Cancellable-infinite-only / elapsed-time methods | 5 / 27 |
 | Methods directly reading environment variables | 47 |
 | Methods directly reading `.cs` source text | 63 |
 
@@ -147,7 +147,7 @@ identifiable in the lane report.
 | T-016 historical test taxonomy | first descriptive-identity batch active in batch J | Remove opaque AP/R/J/K/Slice codes from current test/type names while preserving provenance in comments and ledgers. The 47 `Issue###` files remain an explicit user-decision set because their IDs still connect tests to retail evidence. |
 | T-017 Avalonia ownership | reopened and closed in batch D | The full gate exposed the same compositor ownership class between six newer `MainWindowViewTests` facts. Their six named assertion phases now run in one owned Avalonia application session; 25 fresh-process stress iterations and the complete gate pass. |
 | T-018 stderr observer race | resolved in R2 | Live reader shares writes/deletes; 25 focused repetitions plus the complete gate. |
-| T-019 remaining explicit waits | classified in batch H; four fixed-delay negative oracles resolved in batch M, five remain | Five methods are deterministic cancellation stubs, not wall-clock tests. Preserve intentional real-time contracts and bounded integration polling. The remaining cleanup owners are landblock streamer/pool disposal, headless late-subscriber replay, and two launcher installer/recovery contracts. |
+| T-019 remaining explicit waits | classified in batch H; six fixed-delay negative oracles resolved in batches M/N, three remain | Five methods are deterministic cancellation stubs, not wall-clock tests. Preserve intentional real-time contracts and bounded integration polling. The remaining cleanup owners are headless late-subscriber replay and two launcher installer/recovery contracts. |
 | T-020 exact duplicate bodies/data | resolved in batch K | Four redundant executions were removed. The remaining 11 body-equivalent groups are intentionally split theories with disjoint, meaningfully named datasets; the inventory enforces zero repeated rows within a theory or across body-equivalent theories. |
 | T-021 suspicious assertion shapes | resolved in batch L | The inventory enforces zero `Assert.True(true)` / `Assert.False(false)` sites and reports syntactic self-comparisons for review. All five current self-comparisons assert meaningful determinism or stable identity. |
 
@@ -448,7 +448,7 @@ invocation instead of treating both method-level booleans as equivalent. The
 | Intentional real-time protocol/timeout contract | 4 | Keep with explicit bounds: two Live handshake race delays, the one-second net-probe cadence, and continuous unrelated shutdown drain. |
 | Cooperative yield while virtual-clock/background transport work drains | 8 | Retain for now; prefer an observable receiver/worker signal when that seam exists. The virtual behavioral oracle does not derive from the sleep duration. |
 | Bounded completion/readiness polling | 11 | Retain as integration polling with a terminal assertion and deadline; improve opportunistically with events, not by busy-spinning. |
-| Fixed delay used to prove another operation is still blocked | 9 originally; 5 remain | Batch M replaces four with observed thread wait state. Replace the remaining elapsed-time absence-of-completion checks with an observed wait state or test seam. |
+| Fixed delay used to prove another operation is still blocked | 9 originally; 3 remain | Batches M/N replace six with observed thread wait state. Replace the remaining elapsed-time absence-of-completion checks with an observed wait state or test seam. |
 | Positive completion timeout guard | 1 | Keep. The two-second `WhenAny` in `RuntimeCharacterStateTests` fails only if the operation does not complete; it does not delay a passing run. |
 
 The original nine fixed-delay negative oracles are:
@@ -665,3 +665,34 @@ Batch M verification:
 Five fixed-delay negative oracles remain: the landblock streamer and pool
 disposal contracts, headless concurrent late-subscriber replay, and the two
 launcher installer/recovery contracts.
+
+## Batch N observable landblock-worker joins
+
+The two landblock disposal contracts used 50–100 ms delays to infer that
+`LandblockStreamer.Dispose` was waiting for its dedicated worker threads.
+Batch N replaces those delays with direct observation of the disposer threads:
+
+- `LandblockStreamerTests.DisposeAndConcurrentDisposeWaitForInFlightLoad`
+  observes the primary disposer blocked in a worker `Join`, then observes the
+  concurrent disposer blocked behind the disposal monitor; and
+- `LandblockStreamerPoolTests.Dispose_JoinsEveryWorkerInThePool` observes the
+  disposer blocked while all three controlled worker lanes remain in their
+  loader callbacks.
+
+Both tests then release the loaders, require every disposal thread to join
+within the existing bound, and retain their exception and post-disposal
+inertness checks. Production code is unchanged.
+
+Batch N verification:
+
+- both focused contracts pass;
+- 25 fresh-process iterations of each pass, for 50/50 observed-wait cases;
+- the refreshed inventory reduces direct `Task.Delay` methods from 19 to 17
+  and elapsed-time methods from 29 to 27;
+- the complete 44-project Release build reports zero warnings and zero errors;
+  and
+- the no-retry complete hermetic Release gate remains 14,382/14,382 with zero
+  skips or failures across all 12 test assemblies.
+
+Three fixed-delay negative oracles remain: headless concurrent late-subscriber
+replay and the two launcher installer/recovery contracts.