fieldtest: harvest-sweep — 3 examples, 1 bug / 1 friction / 6 working

Source-blind against the release binary at 120d116, one example per
axis: hs_1_discovery (help -> --folds roster -> --tap spread=mean
without opening source or JSON; fold row at the last warm ts as
documented), hs_2_typo_key (three closed-set refusals — typo'd op key,
undeclared tap, unknown fold — each naming token + valid set, exit 1),
hs_3_three_taps (skipped-tap note fires exactly per skipped tap under
an explicit plan, silent under record-all and bind-all).

Findings routed: the op-key refusal cites the wrong line (points at
the next element; recovery still carried by the key name) -> #336;
declared-tap names have no positive discovery surface (the deferred
#333 view half, evidence now in hand) -> #337. All seven sweep
closures verified working from the outside.

refs #336, refs #337

fieldtests/harvest-sweep/hs_1_discovery.ops.json

@@ -0,0 +1,16 @@
+[
+  {"op": "doc", "text": "SMA crossover bias with two measurement taps for fold discovery"},
+  {"op": "source", "role": "price", "kind": "F64"},
+  {"op": "add", "type": "SMA", "name": "fast", "bind": {"length": {"I64": 3}}},
+  {"op": "add", "type": "SMA", "name": "slow", "bind": {"length": {"I64": 6}}},
+  {"op": "add", "type": "SMA", "name": "px", "bind": {"length": {"I64": 1}}},
+  {"op": "feed", "role": "price", "into": ["fast.series", "slow.series", "px.series"]},
+  {"op": "add", "type": "Sub", "name": "sub"},
+  {"op": "connect", "from": "fast.value", "to": "sub.lhs"},
+  {"op": "connect", "from": "slow.value", "to": "sub.rhs"},
+  {"op": "add", "type": "Bias", "name": "bias", "bind": {"scale": {"F64": 0.5}}},
+  {"op": "connect", "from": "sub.value", "to": "bias.signal"},
+  {"op": "tap", "from": "sub.value", "as": "spread"},
+  {"op": "tap", "from": "px.value", "as": "price"},
+  {"op": "expose", "from": "bias.bias", "as": "bias"}
+]

fieldtests/harvest-sweep/hs_2_typo_key.ops.json

@@ -0,0 +1,12 @@
+[
+  {"op": "source", "role": "price", "kind": "F64"},
+  {"op": "add", "type": "SMA", "name": "fast", "params": {"length": {"I64": 3}}},
+  {"op": "add", "type": "SMA", "name": "slow", "bind": {"length": {"I64": 6}}},
+  {"op": "feed", "role": "price", "into": ["fast.series", "slow.series"]},
+  {"op": "add", "type": "Sub", "name": "sub"},
+  {"op": "connect", "from": "fast.value", "to": "sub.lhs"},
+  {"op": "connect", "from": "slow.value", "to": "sub.rhs"},
+  {"op": "add", "type": "Bias", "name": "bias"},
+  {"op": "connect", "from": "sub.value", "to": "bias.signal"},
+  {"op": "expose", "from": "bias.bias", "as": "bias"}
+]

fieldtests/harvest-sweep/hs_3_three_taps.ops.json

@@ -0,0 +1,16 @@
+[
+  {"op": "doc", "text": "SMA crossover exposing three measurement taps to probe the skipped-tap note"},
+  {"op": "source", "role": "price", "kind": "F64"},
+  {"op": "add", "type": "SMA", "name": "fast", "bind": {"length": {"I64": 3}}},
+  {"op": "add", "type": "SMA", "name": "slow", "bind": {"length": {"I64": 6}}},
+  {"op": "feed", "role": "price", "into": ["fast.series", "slow.series"]},
+  {"op": "add", "type": "Sub", "name": "sub"},
+  {"op": "connect", "from": "fast.value", "to": "sub.lhs"},
+  {"op": "connect", "from": "slow.value", "to": "sub.rhs"},
+  {"op": "add", "type": "Bias", "name": "bias", "bind": {"scale": {"F64": 1.0}}},
+  {"op": "connect", "from": "sub.value", "to": "bias.signal"},
+  {"op": "tap", "from": "fast.value", "as": "fast_ma"},
+  {"op": "tap", "from": "slow.value", "as": "slow_ma"},
+  {"op": "tap", "from": "sub.value", "as": "spread"},
+  {"op": "expose", "from": "bias.bias", "as": "bias"}
+]