feat: prepare beta16 memory and provider evolution

[Obed0101]

Problem

The beta16 implementation was developed on top of an older local branch while origin/dev advanced. It needs to land without deleting any existing dev content.

Solution

• Rebased the owned commits onto origin/dev (c9339c7b) in an isolated integration worktree.
• Added opt-in Memory & Evolution setup, bounded evidence/policy/promotion flow, and adaptive reasoning runtime support.
• Added provider-native/local model identifier validation and dynamic OAuth catalog handling.
• Hardened peer delivery/compaction recovery and prompt-cache status aggregation.
• Added changelog notes for 0.1.44-beta.16.

Scope

The outgoing diff contains 49 changed paths and zero deleted paths against origin/dev. Existing dev files were preserved during conflict resolution.

Verification

• MENDCODE_DB=:memory: bun test --max-concurrency=1 ... — 507 passed, 0 failed, 1,893 expects across 14 affected files.
• bun typecheck — passed.
• git diff --check origin/dev...HEAD — passed.
• git diff --diff-filter=D --name-only origin/dev...HEAD — empty.

Pending gate

The no-token queue/compaction smoke script was attempted but could not complete in this non-interactive environment because it requires a live TTY. Keep this PR draft until the user-visible smoke scenario and required CI/release checks pass.

Release intent

After review/CI and smoke confirmation, promote this candidate through dev and then main, and dispatch the release workflow for 0.1.44-beta.16 with the exact final main SHA.

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