v1.12.0 — Marker 422 fix + Eras + History fields

What's new

Bug fixes

• Repair `create_marker` 422 error — `map` was being sent as a bare string and `world` was omitted entirely; both must be `{ id }` references per the WorldAnvil API. Adds `world_id` as a required parameter on `create_marker` so this can't recur via the MCP surface.

New features

• Era CRUD endpoints (4 new tools): `worldanvil_get_era`, `worldanvil_create_era`, `worldanvil_update_era`, `worldanvil_delete_era`. Eras are timeline subdivisions (e.g. "First Age", "Imperial Period") that group history events into named periods.
• Full marker payload exposed on `create_marker` / `update_marker`: `geo_x`, `geo_y`, `description`, `target_article`, marker `group`, `label_title`, `label_type`, custom `html_marker`, `state`.
• Circle marker styling on `create_marker` / `update_marker`: `circle_radius`, `color_outline`, `color_fill`, `opacity_outline`, `opacity_fill`, `line_weight`.
• 5 new history-event fields: `era_id` (connects events to the new eras endpoints), `timeline_ids`, `category`, `lane`, `backgroundColour`.

Infrastructure

• Normalize `bin` path in `package.json` so `worldanvil-mcp` CLI command is preserved on publish.
• Test suite alignment: marker + category tests were asserting pre-fix buggy payloads; updated to match the corrected handler contracts (`map: {id}`, `targetArticle` field name, `parent` field name on categories).

Stats

• Tool count: 166 → 170
• Available on npm: `npm install worldanvil-mcp@1.12.0`