v0.2.9: Literal Runtime Memory

v0.2.9 makes Runtime Memory safe for arbitrary literal {{...}} text and closes the remaining interpolation failure reported in issue #37.

Fixed

Every {{ opener in USER.md and MEMORY.md is now routed through a dedicated non-recursive prompt variable. Empty, non-ASCII, whitespace-containing, legal, unknown, adjacent, nested, and incomplete groups all reach the model unchanged.
Runtime Memory no longer expands otherwise valid host variables such as {{model}}; memory is quoted data rather than a prompt-template extension point.
The strict host interpolator remains active for Mnemon's static system sections and unrelated plugins, so malformed real prompt references still fail visibly.

Dynamic Runtime Memory snapshots, recalled evidence, managed-document content, and Provider selection data now travel in the delegated run request instead of a child Agent's system persona.
Child personas contain only static responsibilities, tool boundaries, and completion rules. User-controlled text can no longer become a system-prompt interpolation site in archive, compaction, answer, or placement workflows.

Storage files, schemas, tools, RPC contracts, and configuration are unchanged; no data migration is required.
Existing literal braces are preserved exactly. Updating dsh-mnemon and restarting the affected DSH profile is sufficient.

Regression coverage exercises empty, multilingual, whitespace, legal and unknown variable names, adjacent and nested groups, the escape-variable name itself, and incomplete groups.
The complete suite passes with 343 tests; one Windows-only smoke test is skipped only on non-Windows local runs.
Deterministic builds, Headless activation, package validation, and CI on Ubuntu and Windows pass.

See the v0.2.8 release notes for the previous patch release.