feat(mcp): add/remove rank tracking keywords

[Alexi5000]

Related to #125

Problem

Agents can read rank trackers via get_rank_tracker, but cannot add or remove tracked keywords without leaving MCP for the dashboard.

Fix

• add_rank_tracking_keywords → RankTrackingService.addKeywords, with a schedule-aware projected check cost (queued vs live) after the add
• remove_rank_tracking_keywords → RankTrackingService.removeKeywords by trackingKeywordId
• No auto triggerCheck / metrics refresh (avoids silent credit spend)
• Out of scope: create/update config, triggerCheck

Verification

• pnpm exec prettier --write on touched MCP files
• pnpm exec vitest run src/server/mcp/tools/rank-tracking-write-tools.test.ts
• pnpm exec tsc --noEmit
• pnpm exec oxlint on touched files (--type-aware)

Made with Cursor

[sorcerai]

Blocking correctness issue: remove_keywords returns removed=args.keywordIds.length, but the repository silently ignores stale/foreign IDs and duplicate IDs can overcount. The MCP response can therefore claim deletions that did not happen. Please return the actual affected-row count or reject/report non-owned IDs, and cover stale, foreign, and duplicate inputs. Project authorization and no-provider-call ordering otherwise look sound.