docs(governance): secure agent-to-agent secret handover mechanism (#150)

[github-actions]

Adds docs/SECURE_AGENT_SECRET_HANDOVER.md — a token-free, human-out-of-the-loop
protocol for delivering a password/token from a provider agent (FuzeInfra) to a
consumer agent (e.g. FuzeSocial): consumer-authoritative align, in-cluster
dead-drop, sealed-ciphertext handover, or GH-secret push — selected by what the
runner can reach. Never plaintext in an issue/PR/log; verification via one-way
sha256 fingerprint; sealed-ciphertext safe to publish anywhere.

Wires it into governance/datastore-provisioning.md and records the fuzesocial /
fuzesocial_app Postgres allocation (names only; owner+grants verified on prod;
consumer-authoritative credential lives in fuzesocial/fuzesocial-secrets).

Co-authored-by: Israel Weinberg izzywdev@users.noreply.github.com

Closes #150

[izzywdev]

@claude resolve conflicts and get this merge

[claude]

Claude finished @izzywdev's task in 3m 10s —— View job

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✅ Conflicts resolved & PR merged

• Fetch latest main and identify conflicts
• Resolve conflicts
• Push resolution
• Confirm PR is mergeable — merged

What happened: main had been rewritten into a single squashed orphan commit, so this branch shared no common ancestor with it (refusing to merge unrelated histories). A normal merge/rebase wasn't possible, so I rebuilt the branch cleanly on top of the current main and re-applied the three intended changes.

The one real content conflict was governance/datastore-allocations.md: the PR's version predated #153, so taking it verbatim would have deleted the fuzesales / fuzecontact / fuzeservice rows (and the declarative-provisioning note) that landed in main via #153. I resolved it by merging — keeping all of main's rows and just appending the new fuzesocial row.

Final diff vs main — +154 / −0, exactly the PR's stated intent:

File	Change
docs/SECURE_AGENT_SECRET_HANDOVER.md	+146 (new)
governance/datastore-provisioning.md	+7 (credential-delivery block)
governance/datastore-allocations.md	+1 (fuzesocial row, existing rows preserved)

The PR was already approved by @izzywdev, CI passed, and it is now merged into main.
· claude/issue-150-20260705-1012