fix: Reset release sequence number to 0 on each new date

Per spec: the sequence number is a per-day counter that resets on
date change and starts at 0, not 1. The first release of a day is
quant_YYYYMMDD.0.hash, the second .1, etc.

Previous commit fixed *counting* today's releases via the Gitea API
(instead of the always-empty local git tags from a shallow checkout),
but still added +1 on top, which would have produced 1, 2, 3... for
the first, second, third releases of a day instead of 0, 1, 2.
DEPLOY_COUNT is now just RELEASES_TODAY directly.

.gitea/workflows/prepare-release.yml

@@ -4,7 +4,7 @@ on:
   workflow_dispatch:
     inputs:
       version:
-        description: 'Release version (auto-generated if empty, e.g. quant_20260711.1.abc1234)'
+        description: 'Release version (auto-generated if empty, e.g. quant_20260711.0.abc1234 for the first deploy that day)'
         required: false
         type: string
 
@@ -49,11 +49,13 @@ jobs:
             # "quant_20260711.1.*" (three of them: b7591fb, 6ab270f,
             # e49922e, all claiming to be deploy #1). Query the actual
             # Gitea Releases API instead, which reflects real state.
+            # Sequence number resets to 0 on each new date -- the first
+            # release of a day is quant_YYYYMMDD.0.hash, the second .1, etc.
             RELEASES_TODAY=$(curl -sf --connect-timeout 10 --max-time 30 \
               -H "Authorization: token ${GITEA_TOKEN}" \
               "https://gitea.taxbaik.com/api/v1/repos/${{ github.repository }}/tags?limit=50" \
               | jq -r --arg prefix "quant_${TODAY}." '[.[] | select(.name | startswith($prefix))] | length')
-            DEPLOY_COUNT=$((RELEASES_TODAY + 1))
+            DEPLOY_COUNT=$RELEASES_TODAY
 
             VERSION="quant_${TODAY}.${DEPLOY_COUNT}.${COMMIT}"
           else