feat: F008 AI need builder — smart parse, criteria review, follow-up & weighting

Domain: ParsedNeedCriteria, FollowUpQuestion, ParseNeedResult, NeedBuilderStep, WEIGHTING_KEYS/LABELS. Services: weightingService (asset-type profiles), aiService extended with parseNeed (keyword extraction mock, 1.4s delay) and generateFollowUpQuestions. Components: NeedBuilderProgress, NeedInput, ConfidenceFieldBadge, ExtractedFieldRow, CriteriaReviewPanel, FollowUpQuestionCard, FollowUpPanel, WeightingEditor, NeedCardPreview, NeedBuilderErrorState. Page: AINeedBuilderPage replaces AISearch with 4-step flow (input → review → weighting → save).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/components/demand/index.ts

@@ -0,0 +1,10 @@
+export { ConfidenceFieldBadge } from './ConfidenceFieldBadge'
+export { CriteriaReviewPanel } from './CriteriaReviewPanel'
+export { ExtractedFieldRow } from './ExtractedFieldRow'
+export { FollowUpPanel } from './FollowUpPanel'
+export { FollowUpQuestionCard } from './FollowUpQuestionCard'
+export { NeedBuilderErrorState } from './NeedBuilderErrorState'
+export { NeedBuilderProgress } from './NeedBuilderProgress'
+export { NeedCardPreview } from './NeedCardPreview'
+export { NeedInput } from './NeedInput'
+export { WeightingEditor } from './WeightingEditor'