Drop the CI step that ran fabro-agent's twin-mode ignored suites

The step's filter named `fabro-agent` and `fabro-llm`. This branch removes
`fabro-agent`, and `fabro-llm` has no ignored tests, so the step ran nothing
and nextest exited 4 on the empty selection. The agent loop's tests run in
the ordinary suite now and pebble's own suite covers the loop.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

.github/workflows/rust.yml

@@ -125,13 +125,11 @@ jobs:
           cache-on-failure: true
       - uses: taiki-e/install-action@773334c0e05d7e699e4d78234494308223f3a2cf # nextest
       - run: cargo nextest run --locked --workspace --status-level slow --profile ci
-      # Twin-mode e2e suites. These are hermetic (in-process twin provider, no
-      # secrets): FABRO_TEST_MODE defaults to twin, so live-only tests
-      # self-skip. Scoped to the packages whose ignored tests are fully green
-      # in twin mode; widen as the remaining suites are fixed up for CI.
-      # Must not use the e2e nextest profile here: NEXTEST_PROFILE=e2e implies
-      # strict mode, which fails (rather than skips) live tests without keys.
-      - run: cargo nextest run --locked --workspace --status-level slow --profile ci --run-ignored only -E 'package(fabro-llm)'
+      # The twin-mode ignored suites this job once ran belonged to fabro-agent,
+      # which pebble's coding agent replaced; the agent loop's workflow-level
+      # tests run in the suite above, and pebble's own suite covers the loop.
+      # Re-add a `--run-ignored only -E 'package(...)'` step here when a
+      # package has ignored suites that are fully green in twin mode.
 
   sandbox-plugins:
     name: Sandbox plugins (stdio)