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/client/runtime/tsconfig.json

@@ -30,10 +30,10 @@
       "path": "../../compact/compact"
     },
     {
-      "path": "../../session-projection/session-projection"
+      "path": "../../session/session-projection"
     },
     {
-      "path": "../../session-title/session-title"
+      "path": "../../session/session-title"
     },
     {
       "path": "../../llm/llm"

packages/client/ui-conversation/tsconfig.json

@@ -24,7 +24,7 @@
       "path": "../runtime"
     },
     {
-      "path": "../../session-projection/session-projection"
+      "path": "../../session/session-projection"
     },
     {
       "path": "../../llm/token-meter"