fix: use grep -F for baseline lookup to handle Go pointer receivers

The baseline comparison uses grep with the function key as the pattern.
Go pointer receiver methods use (*Type).Method syntax, where (* is
interpreted as a BRE quantifier ("zero or more open-parens") instead
of the literal characters. This causes all pointer receiver functions
to fail lookup and be misclassified as "new functions", triggering
false CRAP threshold violations in consuming repositories.

Switching to grep -F (fixed-string mode) ensures literal matching.
The ^ anchor is dropped because -F does not support anchors, but
collisions are not possible since keys are fully-qualified
file:function paths unique by construction.

Assisted-by: OpenCode (claude-opus-4-6)
Signed-off-by: Marcus Burghardt <maburgha@redhat.com>

Author: marcusburghardt

.github/workflows/reusable_crapload_analysis.yml

@@ -174,7 +174,7 @@ jobs:
 
           # Process current scores
           while IFS=$'\t' read -r key crap gaze_crap; do
-            baseline_line=$(grep "^${key}	" /tmp/baseline-lookup.tsv || true)
+            baseline_line=$(grep -F "${key}	" /tmp/baseline-lookup.tsv || true)
             if [ -z "$baseline_line" ]; then
               # New function
               NEW_COUNT=$((NEW_COUNT + 1))