feat(claude-profile): warn when non-Anthropic provider used with OAuth profile

Add a warning when ANTHROPIC_BASE_URL would be set but the active profile's
.credentials.json would override ANTHROPIC_API_KEY with subscription OAuth,
routing requests to Anthropic instead of the intended provider.

Fixes the MiniMax routing issue: use --profile minimax (~/.claude-minimax/,
no stored credentials) for non-Anthropic providers.

Update presets example to use profile: minimax for quick-minimax preset.
63 tests passing.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

data/claude-profile/presets.yaml.example

@@ -40,9 +40,9 @@ hybrid-day:
   time_horizon: hours
   async: yes
 
-# Quick session via MiniMax (Sonnet-class, pay-per-token, no subscription)
+# Quick session via MiniMax — uses the minimax profile (no OAuth credentials)
 quick-minimax:
-  profile: oreillyit
+  profile: minimax
   mode: quick
   provider: minimax-sonnet
   project: small-scripts

scripts/claude-profile

@@ -425,6 +425,16 @@ PROVIDER_API_KEY_FILE=$(parse_provider_field "$provider_file" api_key_file)
 
 [[ -n "$MODEL_ID" ]] || err "Provider file $provider_file is missing required field: model_id"
 
+# Warn when a non-Anthropic provider is selected but the profile has stored OAuth credentials.
+# Claude Code uses .credentials.json for auth before checking ANTHROPIC_API_KEY, which
+# routes requests to Anthropic regardless of ANTHROPIC_BASE_URL.
+if [[ -n "$PROVIDER_BASE_URL" && -f "$target/.credentials.json" ]]; then
+    echo "Warning: profile '$PROFILE' has stored OAuth credentials ($target/.credentials.json)." >&2
+    echo "         These take precedence over ANTHROPIC_API_KEY and will route requests to Anthropic," >&2
+    echo "         not $PROVIDER. Use a profile without .credentials.json for non-Anthropic providers." >&2
+    echo "         See: claude-profile --help" >&2
+fi
+
 # === Phase 3: Launch ===
 
 # Validate context-load exists

tests/test-claude-profile.sh

@@ -199,6 +199,7 @@ assert_contains "chat default provider is anthropic-haiku" "Provider:        ant
 assert_contains "chat default model ID is haiku" "Model ID:        claude-haiku-4-5-20251001" "$out"
 
 # === Test 14: --preset + --provider mutual exclusion ===
+
 echo
 echo "Test 14: error path — --preset + --provider mutual exclusion"
 out=$(run --dryrun --preset whatever --provider minimax-sonnet)
@@ -206,6 +207,23 @@ rc=$?
 assert_exit_code "preset+provider exits 1" 1 "$rc"
 assert_contains "preset+provider error message" "mutually exclusive" "$out"
 
+# === Test 15: OAuth credentials warning fires for non-Anthropic provider ===
+echo
+echo "Test 15: OAuth credentials warning"
+out=$(run --dryrun oreillyit --mode quick --provider minimax-sonnet)
+rc=$?
+assert_exit_code "credentials warning dryrun exits 0" 0 "$rc"
+assert_contains "warning mentions stored credentials" ".credentials.json" "$out"
+assert_contains "warning names the provider" "minimax-sonnet" "$out"
+
+# === Test 16: No warning when profile has no OAuth credentials ===
+echo
+echo "Test 16: no warning for credentials-free profile"
+out=$(run --dryrun minimax --mode quick --provider minimax-sonnet)
+rc=$?
+assert_exit_code "no-credentials dryrun exits 0" 0 "$rc"
+assert_not_contains "no credentials warning" ".credentials.json" "$out"
+
 # === Summary ===
 echo
 echo "================================"