executor: extract_task_lines for Phase 10 preplan parsing

Pure function parallel to extract_cmd_lines, but more permissive
to accommodate cloud-model output variation: tolerates leading
whitespace (cloud often indents), tolerates extra whitespace after
the colon, strips trailing whitespace. Strict on the literal "TASK:"
prefix.

Returns an array of trimmed strings; empty TASKs and non-TASK lines
dropped silently. Callers cap the list size per cfg.norris.tasks_max.

10 inline unit cases verified: empty/nil, single TASK, mixed CMD+TASK
(only TASKs returned), leading whitespace tolerated, empty-body TASKs
dropped, trailing whitespace stripped, extra-spaces-after-colon AND
no-space-after-colon both tolerated, prose interleaving (3 TASKs
extracted from a realistic cloud response with intro+outro prose),
TASK content with embedded quotes/punctuation preserved.

Nothing in the tree calls this yet (Phase 10 C1 is the foundation
commit; C4 lights it up). No regression.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

executor.lua

@@ -166,4 +166,25 @@ function M.extract_delegate_lines(text)
     return out
 end
 
+-- Phase 10 / #89: extract `TASK: <imperative>` lines from a cloud
+-- preplanner's response. Wire contract for the planning/executor
+-- split: cloud emits a list of imperative TASKs once per :norris
+-- launch, local model executes each.
+--
+-- More permissive than extract_cmd_lines: tolerates leading
+-- whitespace (cloud models often indent) AND leading whitespace
+-- after the colon, AND strips trailing whitespace. Strict only on
+-- the literal "TASK:" prefix.
+--
+-- Returns an array of strings (already trimmed); empty TASKs and
+-- non-TASK lines are dropped silently.
+function M.extract_task_lines(text)
+    local out = {}
+    for line in (text or ""):gmatch("[^\n]+") do
+        local task = line:match("^%s*TASK:%s*(.-)%s*$")
+        if task and task:match("%S") then out[#out + 1] = task end
+    end
+    return out
+end
+
 return M