refactor(orchestration): consolidate steering and retire task tools

[senamakel]

Consolidate detached child steering under tinyagents_orchestration::steering and expose SteerFallback for host queues. A retained finished child now uses that fallback instead of returning AlreadyDone; live children still receive steering through their registered handle. Ownership, supported lanes, request-ID limits and deduplication continue to apply.

Remove the retired task-tool and restart-recovery APIs and their graph exports. Keep SteeringRegistry in tinyagents-tasks, where DetachedTaskRegistry depends on it. Preserve independent middleware, task-store and completion-router tests.

Refs senamakel#59. Part of tinyhumansai/openhuman#8088.

Draft dependency: canonical PRs #496 and #497 must land first. After they merge, merge canonical main into this branch, verify the resulting diff and gates, and mark this PR ready.

Validation:

• At the final head 4acd1a578ede5bfde0e22b7866a3f96d4e4b8773, the full workspace all-target check, task-crate all-target Clippy, 115 task tests, and cargo machete crates pass.
• Before the manifest-only cleanup, full workspace Clippy and tests passed: 5,607 passed, zero failed, 35 ignored, including doctests. Formatting and all-feature rustdoc broken-link checks passed too. The cleanup removes exactly three unused dependency edges and their lockfile entries; source and tests are unchanged.
• The offline composed test calls public steering and verifies the instruction reaches the child harness model request. All five steering end-to-end tests pass.
• The terminal-fallback regression failed against the original implementation (AlreadyDone instead of fallback).
• Current-head CI reruns the full workspace and feature matrix before fork integration.

The wiki is a separate repository. Its reviewed patch is included below for publication after the source change lands; this PR leaves the existing wiki gitlink unchanged.

Wiki follow-up patch

diff --git a/Examples.md b/Examples.md
index 48b9a80..952971c 100644
--- a/Examples.md
+++ b/Examples.md
@@ -377,25 +377,6 @@ let values: Vec<u64> = out.into_successes();
 A total timeout yields `TinyAgentsError::Timeout`; a cancelled token yields
 `TinyAgentsError::Cancelled`.
 
-### List orchestration tasks by kind and creation window
-
-The `orchestrate_list` tool filters spawned tasks by `kind` and a
-creation-time window. *(See `crates/tinyagents-graph/src/orchestration/test.rs`.)*
-
-```rust
-use serde_json::json;
-use tinyagents_graph::{OrchestrationTool, OrchestrationToolKind};
-use tinyagents_harness::tool::Tool;
-use tinyinference::tool::ToolCall;
-
-let list = OrchestrationTool::new(OrchestrationToolKind::List, store);
-let result = list
-    .call(&(), ToolCall::new("l1", "orchestrate_list",
-        json!({ "kind": "sub_agent", "created_after_ms": 0 })))
-    .await?;
-// result.raw is a JSON array of matching task snapshots.
-```
-
 ### Registry introspection
 
 Snapshot the registry (components plus aliases) for audit or UI display, and
diff --git a/Graph-Runtime.md b/Graph-Runtime.md
index d9dd3f5..1d22ae4 100644
--- a/Graph-Runtime.md
+++ b/Graph-Runtime.md
@@ -374,29 +374,21 @@ checkpoint metadata so a UI can render nested runs. The run-id counterpart read
 `ChildRun`s are reported through a `ChildRunSink` and accumulated onto the
 execution.
 
-## Orchestration tools (`tinyagents_graph::orchestration`)
-
-The orchestration module exposes child-work supervision as ordinary harness
-`Tool` implementations a model can call. An `OrchestrationTool` over a `TaskStore`
-(the `InMemoryTaskStore` ships by default) records and controls managed tasks.
-Each task is an `OrchestrationTaskKind` — `Graph`, `SubAgent`, `Tool`, or a
-policy-gated `ExternalProcess` placeholder — moving through an
-`OrchestrationTaskStatus` lifecycle (`Pending`, `Running`, `Awaiting`,
-`Completed`, `Failed`, `CancelRequested`, `Cancelled`, `TimedOut`, `Abandoned`).
-
-`OrchestrationToolKind` enumerates the ten built-in tools, each with a stable
-model-visible name: `orchestrate_spawn`, `orchestrate_await`,
-`orchestrate_cancel`, `orchestrate_kill`, `orchestrate_status`,
-`orchestrate_list`, `orchestrate_timeout`, `orchestrate_race`,
-`orchestrate_yield` (a durable interrupt), and `orchestrate_steer`. Build a
-`OrchestrationTaskSpec`/`OrchestrationTaskRecord` model and register the whole
-set onto a registry with `register_orchestration_tools` (or build them with
-`orchestration_tools` / inspect schemas via `orchestration_tool_schema(s)`).
-`orchestrate_list` filters through `OrchestrationTaskFilter`: the run-tree
-fields (`parent_run_id`, `root_run_id`, `thread_id`, `node_id`, `status`), a
-`kind` label (`"graph"`, `"sub_agent"`, `"tool"`, `"external_process"`), and an
-inclusive `created_after_ms` / `created_before_ms` window in Unix-epoch
-milliseconds (builders: `with_kind`, `created_between`).
+## Detached subagent steering (`tinyagents_orchestration::steering`)
+
+Host code steers a detached child through `steer_detached` or its
+request-id-idempotent variant, `steer_detached_with_request_id`. These
+functions validate the task owner and lane, then deliver through the child's
+live `SteeringHandle` when available. A retained terminal task or a live task
+without a handle is sent through the host-provided `SteerFallback` seam, which
+lets the host enqueue its own metadata, lane, and message. Unknown or pruned
+tasks remain errors. `cancel_for_thread` cancels registered children owned by a
+parent thread.
+
+`SteeringRegistry` remains in `tinyagents_tasks`; `DetachedTaskRegistry` shares
+it with the executor and removes the live handle when a detached task is
+released. The orchestration steering functions depend on that task contract
+without introducing a tasks-to-orchestration dependency.
 
 ## Per-thread goals and todos (`tinyagents_graph::goals`, `tinyagents_graph::todos`)
 

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