fix(memos-local-plugin): infer embedding dimensions for rebuilds

[hijzy]

Summary

• Add embedding maintenance endpoints and viewer controls to repair missing/mismatched vectors or rebuild all vectors after imports/model changes.
• Infer remote embedding dimensions from provider responses instead of exposing dimensions as user config, preventing bge-m3 vectors from being truncated to 384.
• Aggregate multiple explicit feedback corrections in heuristic reward fallback so later negative feedback can lower trace value and priority.

Test plan

• npm run lint
• npm test -- tests/unit/config/load.test.ts tests/unit/config/writer.test.ts tests/unit/embedding/normalize.test.ts
• npm test -- tests/unit/reward/human-scorer.test.ts tests/unit/pipeline/memory-core.test.ts -t "heuristic|submitFeedback aggregates|repairs missing"
• npm test -- tests/unit/pipeline/memory-core.test.ts tests/unit/reward/human-scorer.test.ts tests/unit/server/http.test.ts tests/unit/bridge/methods.test.ts
• npm run build:viewer
• npm pack --json