fix(payments): add atomic bounded payment lifecycle

[drewstone]

Summary

• Add one durable claim, settle, release, reclaim, and recovery state machine.
• Price conservative UTF-8 input, output, provider, tool, and reasoning bounds before execution.
• Enforce one nonce owner across retries, replicas, and mixed gateway versions.
• Retain completed provider work until a late receipt can settle it.
• Abort sandbox streams when the HTTP reader disconnects.

Incident protections

• A replay cannot reuse a signed nonce before its full signed expiry.
• A canceled or crashed request cannot refund work that may have executed.
• A retry cannot release another request's payment reservation.
• Usage storage failure cannot refund already-settled work.

Proof at a32c1f6b9b4f8e16e8b683caa35c88e381d8b83f

• pnpm test — 16 files, 252 tests passed
• pnpm typecheck — passed
• pnpm build — passed
• pnpm pack --dry-run — passed; observer and type entries present
• git diff --check origin/main..HEAD — passed
• git merge-tree --write-tree origin/main HEAD — clean

Release

No package publish or production deployment has occurred.
After approval and merge, publish @tangle-network/agent-gateway@0.7.2, then merge Insurance #93.

[drewstone]

/review

[drewstone]

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[drewstone]

/review 2335d1589f801c77a56fb8521b305582e505ed7a

[drewstone]

/review 2335d15

[drewstone]

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[drewstone]

/review a32c1f6

[drewstone]

/review