fix(gain): match full command for retry detection

Partition the LAG window by the full original_cmd instead of just the
base command name.  The previous approach grouped all invocations of a
bare command (e.g. every `ls`) into one partition, so any pair within
60 s was counted as a retry -- producing 99 %+ false-positive rates on
high-frequency commands.

Matching the full command string means only identical commands re-run
within 60 s are flagged, which is what "retry" actually means.

Reported-by: @aeppling in PR #900

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: tmchow

src/core/tracking.rs

@@ -499,21 +499,7 @@ impl Tracker {
                  END AS base_cmd,
                  timestamp,
                  LAG(timestamp) OVER (
-                   PARTITION BY
-                     CASE
-                       WHEN original_cmd LIKE 'git %' THEN
-                         CASE
-                           WHEN instr(substr(original_cmd, 5), ' ') > 0
-                           THEN substr(original_cmd, 1, instr(substr(original_cmd, 5), ' ') + 3)
-                           ELSE original_cmd
-                         END
-                       ELSE
-                         CASE
-                           WHEN instr(original_cmd, ' ') > 0
-                           THEN substr(original_cmd, 1, instr(original_cmd, ' ') - 1)
-                           ELSE original_cmd
-                         END
-                     END
+                   PARTITION BY original_cmd
                    ORDER BY timestamp
                  ) AS prev_ts
                FROM commands