Webhook Reconciliation

Keep the spec index in sync with git: on every push, re-parse changed specs and refresh the cached content the boards render from.

Problem

If the index drifts from git, the UI shows stale spec content and agents act on outdated requirements — git must stay the undisputed source of truth.

Requirements

• Verify webhook signatures before processing.
• Resolve which specs a push affected from the commit file lists.
• Re-parse and upsert spec_index rows; detect conflicts via blob_sha.
• Tolerate replays and out-of-order deliveries.

Out of Scope

• Bidirectional merge of concurrent UI + git edits (separate spec).