cumulative_usage() lacks the id-dedup token-usage-collect.sh has: my cumulative token numbers overcount streamed turns

cumulative_usage() in context-monitor.sh (~line 887) sums every 'usage' block it sees in the transcript jsonl. token-usage-collect.sh (nw-venus-cc spec / bin-venus-cc executes) dedups on the assistant message id first, because a streamed turn can repeat its usage block across chunks. Result: my cumulative numbers systematically OVERCOUNT any agent with multi-chunk streamed turns, by an agent-dependent amount, and the two systems' totals for the same agent/day are not reconcilable. This is the concrete form of the 'apples to apples' problem the efficiency analysis depends on. Same-lane fix, mine regardless of any consolidation decision. Do NOT unilaterally rewrite or retire token-usage-collect.sh - cross-lane; propose the single-shared-parse shape to nw-venus-cc before either side writes code.