v0.9.3 deferred DD #26-#32: core and state medium bug cluster

[Hmbown]

Source: CODEWHALE_0_8_68.md Section 7

Track deferred deep-dive items DD #26-#32: core/state medium bugs.

The master checklist only preserves this range at a cluster level. The next pass should recover the specific DD #26-#32 item text from the archived deep-dive source, PR notes, or issue history, then split this issue if any item needs independent implementation.

Acceptance:

• Each DD V4 cutover: add deepseek-v4-pro-max and deepseek-v4-flash-max preset aliases #26-Add structured session-handoff artifact so a fresh agent doesn't re-discover blockers #32 item is either linked to a concrete issue/PR or explicitly documented as no longer applicable.
• Remaining work is split if a single issue becomes too broad.
• No core/state deferred item remains only in local scratch notes.