feat: add decision count by status to axme_status output

[George-iam]

The axme_status tool (src/tools/status.ts) returns project status information including total counts of decisions and memories. It would be more informative to break down the decision count by status: active, superseded, deprecated, revoked. This gives the user a quick sense of how many decisions are currently in effect vs. how many have been retired.

Relevant files:

• src/tools/status.ts — modify the status output to include per-status decision counts
• src/storage/decisions.ts — where decisions are loaded from (already has loadDecisions)
• src/types.ts — DecisionStatus type: "active" | "superseded" | "deprecated" | "revoked"

Acceptance criteria:

• axme_status output includes a breakdown like "Decisions: 45 total (40 active, 3 superseded, 2 deprecated)"
• Decisions with undefined status are counted as "active" (backward compat)
• npm run build passes