refactor(schema): rename V2 session events and normalize payloads (#35217)

specs/v2/schema-changelog.md

@@ -904,3 +904,17 @@ Compatibility:
 
 - Existing Context Epoch rows migrate in place by dropping the obsolete selection and pending-replacement columns.
 - Model and agent switches no longer discard earlier chronological System Context updates by forcing a new baseline.
+
+## 2026-07-03: Normalize Session Event Names And Envelope Time
+
+- Drop the experimental `session.next.` prefix from current Session event names.
+- Rename `agent.switched` to `agent.selected`, `model.switched` to `model.selected`, and `prompted` to `prompt.promoted`; add `prompt.admitted` as the durable prompt admission record.
+- Add an envelope-level `created` timestamp stored on each event row; payload-level `timestamp` fields are removed.
+- Remove projection-only `messageID` fields from selected/message-producing events; projected message IDs derive from the event ID. `revert.committed.messageID` remains, and `forked.messageID` is now `forked.from`.
+- Rename `session.moved.subdirectory` to `subpath` and normalize event-related schema identifiers.
+
+Compatibility:
+
+- V2 durable events and projections are experimental and are reset by `20260703090000_reset_v2_event_rename_sweep`; existing V2 event rows, event sequences, projected session messages, and admitted inputs are wiped.
+- All renamed durable event types restart at version 1 under their normalized names.
+- Generated Promise, Effect, and legacy JavaScript SDK surfaces were regenerated from the normalized schemas.

specs/v2/session.md

@@ -114,7 +114,7 @@ Before each provider turn, the runner estimates the complete model-visible reque
 
 Compaction keeps the full transcript durable while replacing its active model representation with one hidden checkpoint containing a structured rolling summary and token-bounded serialized recent context. Provider-native assistant, reasoning, and tool messages never survive across the boundary, avoiding signature and encrypted-reasoning failures when the earlier prefix changes.
 
-`session.next.compaction.started.1` durably identifies the attempt. Compaction deltas are live-only progress. `session.next.compaction.ended.1` durably stores the final summary and serialized recent context; only this completed event projects a model-visible compaction message. On the next provider attempt, the runner observes that completed compaction and directly renders a fresh Context Epoch baseline. A failed or interrupted attempt therefore leaves the previous history boundary active.
+`compaction.started.1` durably identifies the attempt. Compaction deltas are live-only progress. `compaction.ended.1` durably stores the final summary and serialized recent context; only this completed event projects a model-visible compaction message. On the next provider attempt, the runner observes that completed compaction and directly renders a fresh Context Epoch baseline. A failed or interrupted attempt therefore leaves the previous history boundary active.
 
 Repeated compactions update the previous structured summary with newly compacted messages. The runner then reloads projected history and executes the original pending turn.
 
@@ -170,9 +170,9 @@ The coordinator's active registry is also the source for `sessions.active()`. It
 
 Inbox promotion coalesces pending steers in durable admission order. Once continuation would otherwise end, it promotes one queued input at a time in FIFO order. Add explicit inbox backlog and steering-batch limits before exposing broad multi-caller admission or untrusted queue growth.
 
-Eager local-tool execution is intentionally unbounded in the current local slice. This minimizes tool latency but does not increase SQLite settlement throughput: Session-event publication remains serialized per provider turn. Before broadening exposure, revisit per-turn call limits, output truncation, and operational backpressure using observed workloads. The `session.next.*` event schemas remain experimental and unshipped; databases created by earlier experimental builds are disposable rather than compatibility targets.
+Eager local-tool execution is intentionally unbounded in the current local slice. This minimizes tool latency but does not increase SQLite settlement throughput: Session-event publication remains serialized per provider turn. Before broadening exposure, revisit per-turn call limits, output truncation, and operational backpressure using observed workloads. The normalized Session event schemas remain experimental and unshipped; databases created by earlier experimental builds are disposable rather than compatibility targets.
 
-The synchronized `session.next.*` event family and projected Session-message model predate this branch. This slice refines their replay contract: projected Session messages retain their source aggregate sequence so canonical context ordering and `sessions.messages(...)` pagination follow durable event order even when caller-supplied IDs or timestamps do not. Consumers can use `sessions.log({ sessionID, after? })` to replay durable `session.next.*` events after an aggregate sequence cursor, then tail durable events without a race. Live-only text, reasoning, and tool-input fragments remain available through EventV2 subscriptions for connected renderers; they are intentionally absent from the replayable Session stream.
+The normalized Session event family and projected Session-message model predate this branch. This slice refines their replay contract: projected Session messages retain their source aggregate sequence so canonical context ordering and `sessions.messages(...)` pagination follow durable event order even when caller-supplied IDs differ; event time is carried by the envelope `created` field rather than duplicated in payloads. Consumers can use `sessions.log({ sessionID, after? })` to replay durable Session events after an aggregate sequence cursor, then tail durable events without a race. Live-only text, reasoning, and tool-input fragments remain available through EventV2 subscriptions for connected renderers; they are intentionally absent from the replayable Session stream.
 
 The first `sessions.log(...)` contract is durable-only during both replay and live tailing. This keeps one cursor equal to one persisted aggregate sequence and is sufficient for reconnect-safe consumers. A later UI-facing API may optionally interleave live-only deltas while connected, but those fragments must remain explicitly ephemeral: they cannot advance the durable cursor, replay after reconnect, or be mistaken for publication boundaries.