docs: dsh 0.1.2 alpha: session-event format and settings API break, new Remote API cookbook

[github-actions]

The dsh docs were refreshed to match a development snapshot that has moved
well past the last tagged release: the npm page now tracks a new
0.1.2-alpha.2→.5 train (shipped daily 2026-08-30 → 09-02, latest still
0.1.1-rc.2), and 46 mirrored pages were rewritten upstream with interface
changes, not just wording. dsh is an unstable developer preview with no
migration path, so plugin authors on the master/alpha line should expect to
recompile and re-typecheck against these changes.

• Session event log format hardened. Sequence positions are now branded
  types (SessionSeq, SessionLogOffset, SessionSeqCursor,
  OptionalSessionSeq) threaded through SessionEvent, SurfaceOp, and every
  compaction/* / command/* / session-surface type; event payloads gain an
  ignorable?: true skip marker (an unrecognized required event must now
  refuse reconstruction rather than be dropped); sessions track an
  inheritedEventCount fork-lineage cut; and Session.events is replaced by
  snapshotEvents() / eventAt() / ownEvents() / isOwnSeq(). Downstream
  plugins that merge custom event types or read the log will hit all of this.
• Settings plugin API changed shape. The standalone
  installSettingsSection(ctx, …) helper and settingsNamespace() brand are
  gone; consumers now ctx.inject(['settings']) and call
  ctx.settings.installSection(owner, ns, schema, entry, hooks) (see the
  rewritten adding-a-settings-card cookbook). Namespace strings are validated
  as lowercase-hyphenated identifiers and remote failures now throw
  RemoteError with slash codes (settings/conflict, settings/rejected)
  instead of TypertRemoteFailure and kebab codes.
• New cookbook: adding a Remote API (new page) — the five-step recipe for
  adding a ctx.remote.<namespace>.<method>() endpoint: @Remote declaration,
  one RemoteError code table merged into RemoteErrorDetailsMap, manifest
  generation, the typed client call, and Host/Client testing. Worth reading
  before any remote-call work.
• Remote/gateway config shifts. The Typert gateway error taxonomy moved to
  RemoteError with gateway/* codes carried through unchanged; the
  session-controller adds a coldBlankProbeMaxEvents projection gate; the
  API-gateway WebSocket heartbeat default drops 30000 → 2000 ms.
• Package map churned (module-graph.md, config-catalog): agent-spine-demo
  and tool-subagent-report are gone, code-runtime-python moved under
  experimental, and several plugins (agent-instructions, agent-loop,
  agent-presets) newly require sessionProjections — session projection
  callbacks and cached/cold snapshots now take an inheritedEventCount
  argument.
• Also in this run (minor, not dsh): .metadata.json flags two older news
  pages (news1226 DeepSeek-V3, news251201 V3.2) as served-fallback-shell —
  the reverse of the previous clean fetch — so a future full refetch may gut
  them; file content is unchanged in this tree.