CI: wipe auth instead of reset-password in the agent-guides jobs (#7603)

Since #7573 reset-password rotates the credential in place and prints the new
passphrase to stdout, so these four steps were writing it unmasked into the job
log and no longer produced the clean auth state their name implies. They never
read .bootstrap_password (serve-unsloth-run.sh only parses the sk-unsloth key
off the banner), so the wipe the other ten studio-* workflows already use is the
right shape here too.

.github/workflows/local-agent-guides-ci.yml

@@ -167,7 +167,9 @@ jobs:
       # ── boot the server under test (factored helper) ──────────────────
       - name: Serve unsloth run --disable-tools (gemma-4-E4B)
         run: |
-          unsloth studio reset-password
+          # Wipe, not reset-password: since #7573 the reset rotates in place and
+          # prints the new passphrase, which would land unmasked in the job log.
+          rm -rf ~/.unsloth/studio/auth
           bash .github/scripts/serve-unsloth-run.sh \
             --gguf-file "$GITHUB_WORKSPACE/gguf-cache/${GGUF_FILE}" \
             --port "$STUDIO_PORT" --log-dir logs \
@@ -371,7 +373,7 @@ jobs:
 
       - name: Serve unsloth run --disable-tools (gemma-4-E4B)
         run: |
-          unsloth studio reset-password
+          rm -rf ~/.unsloth/studio/auth
           bash .github/scripts/serve-unsloth-run.sh \
             --gguf-file "$GITHUB_WORKSPACE/gguf-cache/${GGUF_FILE}" \
             --port "$STUDIO_PORT" --log-dir logs \
@@ -554,7 +556,7 @@ jobs:
 
       - name: Serve unsloth run --disable-tools (gemma-4-E4B)
         run: |
-          unsloth studio reset-password
+          rm -rf ~/.unsloth/studio/auth
           bash .github/scripts/serve-unsloth-run.sh \
             --gguf-file "$GITHUB_WORKSPACE/gguf-cache/${GGUF_FILE}" \
             --port "$STUDIO_PORT" --log-dir logs \
@@ -718,7 +720,7 @@ jobs:
 
       - name: Serve unsloth run --disable-tools (gemma-3-270m)
         run: |
-          unsloth studio reset-password
+          rm -rf ~/.unsloth/studio/auth
           bash .github/scripts/serve-unsloth-run.sh \
             --model "$GGUF_REPO" --gguf-variant "$GGUF_VARIANT" \
             --port "$STUDIO_PORT" --log-dir logs \