Root-caused and worked around the actionability-gate resolve bug blocking session open. OPEN.php's step-5 pickup URL points to a deprecated redirect stub that drops POST bodies, combined with resolve/deliver reading $_POST only -- fixed by calling the real endpoint directly. Flagged to Server[40]/CC for a permanent fix.

Diagnosed actionability-resolve failure via live source read (file-reader.php) instead of guessing further; identified two-part root cause (stale redirect URL in OPEN.php step 5 + POST-only param read in inbox-api.php resolve/deliver); resolved all 4 blocking items by calling backend/api/critical/inbox-api.php directly; logged K343 to memory pipeline; flagged Server[40]/CC via inbox msg 1003 with two suggested fixes; ran CHECKPOINT.php (addressed LEGACY staleness and missing memory-pipeline entry warnings); ran SYNC.php (all_clear, 120 items picked up, snapshot confirmed current).