feat(delegation): uncap max_spawn_depth (floor 1, no ceiling) (#39772)

* fix: respect disabled auto-compaction on context overflow

Port from anomalyco/opencode#30749.

When compression.enabled is false, NO automatic compaction trigger may
fire. The proactive token-threshold paths (preflight + post-response
should_compress gate) already honoured the setting, but the three
provider-overflow recovery paths in the agent loop — long-context-tier
429, 413 payload-too-large, and context-overflow — called
_compress_context() unconditionally, silently compressing and rotating
the session against the user's explicit choice.

Add a single guard at the top of the overflow-recovery dispatch: when
compression is disabled and the error is one of those three overflow
classes, surface a terminal error (compaction_disabled: True) telling the
user to /compress manually, /new, switch to a larger-context model, or
reduce attachments. Manual /compress (force=True) is unaffected — it never
enters this loop.

Tests: new TestOverflowWithCompactionDisabled (413 + 400 overflow don't
compress when disabled; control case still compresses when enabled).
Existing overflow-recovery tests updated to enable compaction explicitly
(they verify the recovery fires); fixture defaults flipped to True to
match production (compression.enabled defaults to True).

* feat(delegation): uncap max_spawn_depth to match max_concurrent_children

Removed the hard ceiling of 3 on delegation.max_spawn_depth. Depth now has
a floor of 1 and no upper limit, mirroring max_concurrent_children. Cost
(each level multiplies API spend) is the practical limiter, not a constant.

- delegate_tool.py: drop _MAX_SPAWN_DEPTH_CAP, _get_max_spawn_depth() floors
  at 1 instead of clamping to [1,3]; depth-limit error string reworded
- config.py / cli-config.yaml.example: doc comments say floor 1, no ceiling
- docs (configuration, delegation, delegation-patterns): range 1-3 -> >=1
- tests: convert clamp-above-3 change-detector into a no-ceiling invariant,
  drop the _MAX_SPAWN_DEPTH_CAP==3 snapshot assert, fix warning-text assert

hermes_cli/config.py

@@ -1677,9 +1677,9 @@ DEFAULT_CONFIG = {
                                  # "low", "minimal", "none" (empty = inherit parent's level)
         "max_concurrent_children": 3,  # max parallel children per batch; floor of 1 enforced, no ceiling
         # Orchestrator role controls (see tools/delegate_tool.py:_get_max_spawn_depth
-        # and _get_orchestrator_enabled).  Values are clamped to [1, 3] with a
-        # warning log if out of range.
-        "max_spawn_depth": 1,        # depth cap (1 = flat [default], 2 = orchestrator→leaf, 3 = three-level)
+        # and _get_orchestrator_enabled).  Floored at 1, no upper ceiling —
+        # raise deliberately, each level multiplies API cost.
+        "max_spawn_depth": 1,        # depth (1 = flat [default], 2 = orchestrator→leaf, 3+ = deeper)
         "orchestrator_enabled": True,  # kill switch for role="orchestrator"
         # When a subagent hits a dangerous-command approval prompt, the parent's
         # prompt_toolkit TUI owns stdin — a thread-local input() call from the