fix(telemetry): drop duplicate Beast MetricsRegistry test + remove author-local symlink

- `src/test/telemetry/MetricsRegistry_test.cpp` (Beast `unit_test::suite`
  format under `src/test/`) duplicates the GTest version already
  maintained at `src/tests/libxrpl/telemetry/MetricsRegistry.cpp`.
  Project rule (`tasks/lessons.md` §Test Format): all new tests use
  GTest under `src/tests/libxrpl/`. The GTest version exercises the
  same four cases (disabled construction, start/stop lifecycle, recording
  no-op, destructor-calls-stop). Deleting the Beast duplicate eliminates
  drift and keeps the test authoritative in one place.
- Drop the matching `test.telemetry > xrpl.basics/xrpl.core/xrpld.telemetry`
  entries from `.github/scripts/levelization/results/ordering.txt`
  because `xrpl.test.telemetry` (the GTest binary) retains its own
  entries; the removed ones belonged to the deleted Beast suite.

- `.claude/instructions.md` was committed as a symlink to an
  author-local absolute path (`/home/pratik/sourceCode/personal/Rippled/
  instructions.md`) that does not exist for any other contributor or in
  CI. Remove the symlink from git tracking and add `.claude/` to
  `.gitignore` so future agent commits do not re-add per-developer
  settings.

.github/scripts/levelization/results/ordering.txt

@@ -186,9 +186,6 @@ test.shamap > xrpl.basics
 test.shamap > xrpl.nodestore
 test.shamap > xrpl.protocol
 test.shamap > xrpl.shamap
-test.telemetry > xrpl.basics
-test.telemetry > xrpl.core
-test.telemetry > xrpld.telemetry
 test.toplevel > test.csf
 test.toplevel > xrpl.json
 test.unit_test > xrpl.basics