refactor(session): fold the session family into packages/session/

git mv the 12 packages from session-persistence/, session-projection/,
session-title/, and telemetry/ into one session/ group per the
regrouping RFC; merge the four group READMEs into one bilingual
triplet; rewrite the group segment in tsconfig references (intra-group
references shorten to ../<pkg>), tsconfig.base.json paths/globs,
knip.json keys, vitest include, gate scripts, and authored doc/note
citations; regenerate module graph, doc graphs, catalogs, and the
lockfile importer keys. No npm names change.

Full unit suite: 8779 passed; the 18 reported failures reproduce as
env flakes (ambient-proxy IPv6 tunneling, watched-dir inotify
timeouts under parallel load) — each passes in isolation with
NO_PROXY set, matching their known pre-existing behavior on master.

packages/session/session-projection/src/invariant.ts

@@ -0,0 +1,38 @@
+/**
+ * Package-owned invariant companion for `@deepseek-ai/dsh-session-projection`.
+ * @module @deepseek-ai/dsh-session-projection/invariant
+ */
+
+/* jscpd:ignore-start */
+import type { Context } from 'cordis'
+import type { InvariantInstaller } from '@deepseek-ai/dsh-invariants'
+
+const PACKAGE_NAME = '@deepseek-ai/dsh-session-projection'
+
+/** Cordis companion plugin name. */
+export const name = 'session-projection-invariant'
+/** Service required before the companion can reserve package ownership. */
+export const inject = ['invariants']
+
+/**
+ * No runtime invariant: the registry's own contracts (duplicate-key and
+ * stateVersion rejection, effect-tied removal, the Object.is change gate) are
+ * enforced synchronously inside the service and proven by its spec, the
+ * drive relation (every committed `session/event` passes every unit) would
+ * require re-running the drive to check — duplicating the implementation
+ * rather than detecting drift — and the served-value relation (every served
+ * key has a live registration) lives on each carrier's wire path, which
+ * emits no cordis event this companion could observe; carrier specs assert
+ * it. Synchronous-unit discipline is enforced as far as practical by the
+ * boundary `schema.parse` (a Promise-returning view fails loudly).
+ */
+const install: InvariantInstaller = () => {}
+
+/**
+ * Register this package's invariant companion.
+ * @param ctx - Cordis context carrying the invariant service.
+ * @returns the installed registration's disposer after setup succeeds.
+ */
+export const apply = (ctx: Context): Promise<() => void> =>
+  Promise.resolve(ctx.invariants.register(PACKAGE_NAME, install))
+/* jscpd:ignore-end */