v0.2.0: getcontext/writecontext + count-sealed archive shards

Changed

• BREAKING: /mosyn-list is renamed to /mosyn-getcontext and /mosyn-wrap is renamed to /mosyn-writecontext. The pair now self-documents the protocol rhythm: getcontext is the read half, writecontext is the write half. Update your .claude/commands/ copies; the command count stays six.
• Archive read-back model corrected: memwal_restore re-indexes a namespace and returns counts only; memwal_recall fetches verbatim text. The 0.1.0 description ("read back only by restore, never semantically recalled") was wrong; archive isolation is by namespace, and deliberate read-back is restore-then-recall.
• Retrieval guidance: query by scope plus topic. Type prefixes ([DECISION], [FAILURE], ...) nudge ranking but never filter; never query by type alone.
• The session-end batch prefers memwal_remember_bulk, with sequential memwal_remember as the fallback.

Added

• Count-sealed archive shards. Shard s0 is the plain <namespace>-archive; when a shard reaches 80 blobs, the session-end write seals it: one compaction blob (titles plus one-line outcomes) goes to <namespace>-archive-index, the manifest fact is superseded to name the next active shard, and the summary lands there. The fresh-machine rebuild walks the index for sealed history and reads only the active shard in full, checksummed at every step, so reconstruction is complete at any session count. The seal loop was exercised live on Walrus Mainnet.
• TODO retirement rule. A TODO completed in a session is superseded by the STATUS fact that reports it done, keeping stale TODOs out of recall.

Full details in the CHANGELOG.