v0.10.0: n8n_diff_workflow

Closes the snapshot/restore loop opened in 0.7/0.8 — you could save and restore but had no way to see what changed.

Added

• n8n_diff_workflow — read-only semantic diff between a workflow's current state and a snapshot. Inputs: id plus exactly one of snapshotPath (absolute file path; ~ resolved) or snapshot (inline object). Snapshot accepts both shapes: flat (n8n_save_workflow / n8n_delete_workflow backup) and nested (n8n_get_workflow(includeDefinition=true)). Returns counters in summary (added/removed/modified, plus nameChanged/connectionsChanged/settingsChanged) and a diff payload with per-node fieldsChanged paths walking one level into parameters (e.g. parameters.command, parameters.url).

Notes

• Two-pass node matching: id-first, name-fallback for any unmatched nodes. Handles legacy/hand-edited snapshots without forcing a "1 added + 1 removed" false signal when one side is missing ids.
• Cosmetic noise suppression: position and webhookId changes are suppressed by default; toggle with ignoreCosmetic: false.
• Bounded output: per-node detail capped at maxModifiedDetails (default 50, max 500) with explicit nodesModifiedTruncated flag; summary counters are uncapped.
• Pairs with n8n_save_workflow (which writes the snapshot) and n8n_audit_browser_bridge_usage (which surfaces calls — diff tells you whether they've drifted).

15 new tests, full suite 145/145 green.