docs: Add ADR-018 through ADR-023 and DDD for temporal tensor store

Extends ADR-017 with detailed architecture for block-based temporal
tensor compression. Introduces 6 new ADRs covering storage engine,
tiered quantization formats, temporal scoring algorithm, delta
compression/reconstruction, WASM API, and benchmarking criteria.
Adds comprehensive DDD with 5 bounded contexts mapping to the
proposed 6-crate workspace layout.

ADR-018: Block-based storage engine with BlockKey/BlockMeta model,
         append-only MetaLog, tiered data files, CRC32 checksums
ADR-019: 8/7/5/3-bit quantization formats with two-level scale,
         Tier0 compression-to-zero, codec_bits bit packing
ADR-020: EMA + popcount + recency scoring, hysteresis, budgeted
         maintenance ticks, fast exp approximation
ADR-021: Read/write paths, sparse delta format, delta chain
         compaction, factor-based reconstruction policies
ADR-022: WASM exports (tts_init/put/get/tick/stats), host-imported
         BlockIO, cross-platform strategy (native/Node/browser/edge)
ADR-023: Zipf simulation acceptance test (1M blocks, 10M accesses),
         microbench targets, failure mode catalog

DDD: 5 bounded contexts (Block Management, Quantization, Temporal
     Scoring, Storage Engine, Delta & Reconstruction) with aggregate
     roots, domain events, repository interfaces, and context map.

Total: 8,084 lines across 7 documents.

https://claude.ai/code/session_01Ksy165BL5nGpVoWaAfTE7t

Author: claude