fix(memory): restore direct conversation extraction and subject attribution

[axAilotl]

Direct conversation facts were being dropped when structured attribution could not resolve transport identities, preferred names, companion sources, or non-speaking subjects. This restores extraction while preserving separate source and subject identities.

• Use canonical journal/turn identity for a sole DM human, plus canonical Discord, companion, and external-session identity namespaces. Name lookup accepts a unique live display name or nickname; it does not guess unstored aliases by stripping suffixes.
• Accept known source and subject aliases in direct conversations while keeping strict group routing bound to journal names.
• Route companion self-knowledge to companion ownership. Mixed user/assistant citations can use the sole human when the model omits the source name; multi-human exchanges remain ambiguous and companion-only paraphrases cannot establish human facts.
• Resolve named third parties against existing live contacts. Unknown subjects remain explicitly unbound on first mention; recurring relational or explicitly attributed semantic facts may create a mention-only stranger contact through the existing contact-tracking gate and relink earlier memories. Group semantic contact creation is unchanged.
• Share ownership and name-matching predicates and separate implicit speaker routing from structured attribution.

Validation: npm run gate:pre-pr passed on 933039041554e18e9b4c886b741f464bb749fe8e: build, typecheck, structural hygiene, 191 selected tests, 19,225 unit tests (5 skipped), and 850 integration tests. Focused regressions cover group alias rejection, unnamed mixed citations, first-mention non-creation, recurring semantic subject linking, and contact-tracking gates.

Beads: psfn-framework-d5e0p.6, .7, .9, .10, .12. Acceptance wording for .7 and .12 now explicitly describes the stored name fields and existing recurring-mention threshold. Live validation remains pending deployment. Historical data repair, transcript re-extraction, and retrieval changes are separate work.