feat: fleet comms wire schemas (event envelope, channel metadata, message metadata) v1

[andrei-hasna]

Summary

Registers three machine-validatable fleet comms wire schemas + validators per fleet comms workflow v1.1. Todos task: 41ea5a6e (parent tracking task 843cfb62). Wire schemas belong in open-contracts, not knowledge (v1.1 amendment 2; knowledge item hasna-knowledge-taxonomy).

Schemas (all .strict(), registry-integrated, hasna.*.v1 ids minted in contracts per governance decision #2, k_mr6fvzgm_wrcb2t)

• hasna.comms_event_envelope.v1 — namespaced <source>.<entity>.<action> type (2-4 lowercase segments), severities info|notice|breaking|critical, scope fleet|package|machine, affected_packages/affected_machines, action_required, ack_by, mandatory dedupe_key. Cross-field rules: package scope requires affected_packages; machine scope requires affected_machines; ack_by requires action_required; fleet.freeze/fleet.unfreeze pinned critical + fleet-scoped + action-required.
• hasna.comms_channel_metadata.v1 — the metadata.channel_schema object: class enum fleet|package|product|loop-lane|initiative|personal, noise quiet|work|firehose, initiative channels require owner + machine-evaluatable until horizon (ISO date, UTC timestamp, or gate:<todos-id>), archived-channel successor pointer.
• hasna.comms_message_metadata.v1 — severity-tag metadata for [FREEZE]/[UNFREEZE]/[BREAKING]/[CUTOVER]/[POLICY]/[RELEASE] exact-case first-token posts; tag + full envelope ride in --metadata, never parsed from text; per-tag severity bounds; FREEZE/UNFREEZE pinned to fleet.freeze/fleet.unfreeze both directions.

Validators exported for hooks/loops/publishers (validate before emit/post)

• One severity mapping table: COMMS_EVENT_TYPES / COMMS_SEVERITY_TAG_INFO (+ bijection consistency tests), defaultSeverityForCommsEventType.
• extractCommsSeverityTag (exact-case first token), commsSeverityTagToken, validateCommsTaggedMessage (text token + metadata schema + tag/text match).
• Generic registry paths work too: validateContract/parseContract/validateEmbeddedContract, CLI contracts validate --schema hasna.comms_event_envelope.v1 ....

Version: 0.4.1 -> 0.5.0 (additive minor). Human-facing rules live in knowledge items hasna-agent-comms-protocol / hasna-agent-comms-envelope; these schemas are the machine-validatable source of truth those items cross-reference.

Verification

• bun run verify:release green: typecheck, 169 pass / 7 skip / 0 fail (baseline 142), conformance over all fixtures incl. the 6 new comms valid/invalid fixtures, build, dist smoke, pack dry-run.
• Adversarial review (high effort, 8 angles) run on the diff: 2 findings surfaced and fixed in this PR (tag<->event-type bijection consistency tests; until horizon tightened from free-form string to date/timestamp/gate-id). Refuted candidates documented in the task log.
• Note: bun test with a stale dist/ present fails pre-existing no-cloud-scan tests (repo-known; verify:release rm-rfs dist first). Not introduced by this PR.

Fixtures

6 new examples: comms-{event-envelope,channel-metadata,message-metadata}.{valid,invalid}.json wired into the examples + conformance suites with exact expected issue paths.