feat: add V-PROGRAM message type support (phase 1)

[odesenfans]

What

Phase-1 CCN support for the new V-PROGRAM message type (SEV-SNP verifiable programs, VerifiableProgramContent from aleph-im/aleph-message#158): parse, price, store, and display.

• Parsing: PendingVProgramMessage, CONTENT_TYPE_MAP entry, tag extraction from content.metadata.tags.
• API: VProgramMessage response model wired into MESSAGE_CLS_DICT, the AlephMessage discriminated union, and the headers content format, so V-PROGRAM rows render in every /messages endpoint (list filters, single message, pending, rejected, websocket).
• Pricing: V-Programs are priced on the existing instance_confidential tier (compute units + declared extra volumes; the runtime bundle and workload are STORE-paid artifacts and deliberately carry no execution-volume cost). Cost-estimation schemas and both price endpoints (GET /api/v0/price/{item_hash}, POST /api/v0/price/estimate) support the type.
• Processing: dedicated VProgramMessageHandler validates the credit balance (V-Programs are credit-only by schema) and persists cost rows; recurring credit billing picks the rows up generically. process/forget keep no side tables in phase 1: the message row is the source of truth.

No DB migration is needed (the message type column is a plain varchar).

Phase-1 scope (deliberate)

• No measurement validation and no runtime/workload ref checks (phase 2 will add CCN-side measurement recomputation per the confidential VM protocol design).
• No vms table rows, no VmType member: v-programs do not appear in vms accessors yet, and forgetting a STORE file referenced by a v-program workload is not blocked.
• No amend/replaces chain validation.

Merge gate

pyproject.toml pins aleph-message to the head commit of aleph-im/aleph-message#158. Swap it for the released version once that PR ships in a release, and re-run the type checks, before merging.

Tests

13 new tests (schema round-trips with the canonical cross-SDK fixture, cost tier selection, end-to-end pipeline processing/rejection against Postgres, price and display endpoints). Full suite: 871 passed, 10 skipped, 0 failed; black/ruff/isort clean; mypy clean.

🤖 Generated with Claude Code

[foxpatch-aleph]

Well-structured phase-1 implementation for V-PROGRAM support. The handler, cost service, schemas, and controllers all follow existing patterns correctly. V-Programs are priced on the INSTANCE_CONFIDENTIAL tier with VerifiedVolume entries correctly excluded from execution-volume costs. The credit-only payment enforcement is explicit. 13 new tests provide thorough coverage of parsing, pricing, pipeline processing, API display, and GC removal. The only merge gate is swapping the aleph-message git pin for a released version, which is already documented in the PR description.

pyproject.toml (line 33): Merge gate: this git pin to aleph-message#158 must be swapped for a released PyPI version before merging, as noted in the PR description.