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.

vitest.config.ts

@@ -224,7 +224,7 @@ export default defineConfig({
         // cover and remove with the client test lane above.
         'packages/ui/commands/src/index.ts',
         'packages/ui/commands/src/invariant.ts',
-        'packages/session-projection/session-projection/src/index.ts',
+        'packages/session/session-projection/src/index.ts',
         ...windowsUnsupportedPackages.map(path => `${path}/src/**/*.ts`),
         ...windowsCoverageExclusions,
         ...pwshCoverageExclusions,