refactor: dead-code cleanup + drop the lib/types shim (slice 9)

- Delete orphaned components (theme-provider, task-claim-button), the unused
  roleDisplayName helper, the fully-dead cleanupRateLimits, the 6 never-imported
  validation schemas (signIn/signUp/createSpace/joinSpace — a replaced auth flow;
  proposalStatuses; updateAreaLeadRoleSchema).
- Migrate all @/lib/types importers to the canonical @/types/domain and delete
  the compatibility shim.

tsc 0, 635 tests green, lint clean.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

lib/validations/governance.ts

@@ -4,7 +4,6 @@ import { flexibleDateTime } from './primitives'
 // ─── Governance: proposals ───────────────────────────────────────────────────
 
 export const proposalTypes = ['bylaw_change','board_action','membership_vote','advisory_poll','recall','budget'] as const
-export const proposalStatuses = ['draft','open','decided','withdrawn','expired'] as const
 export const thresholdRules = ['simple_majority','two_thirds','three_fourths','unanimous'] as const
 export const votePositions = ['yes','no','abstain','recused'] as const