fix: remove constraints.txt as hard pip constraint in deploy

- Replace -c constraints_url with simple pip install -r requirements.txt
- constraints.txt SHA drift was causing pip version conflicts
- Let pip resolve dependencies naturally without stale constraints

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

Author: Pigbibi

.github/workflows/sync-cloud-run-env.yml

@@ -342,10 +342,7 @@ jobs:
         run: |
           set -euo pipefail
           python -m pip install --upgrade pip
-          grep -vE "^\s*(#|$)|git\+" requirements.txt | xargs -r python -m pip install -c https://raw.githubusercontent.com/QuantStrategyLab/QuantPlatformKit/main/constraints.txt
-          grep 'git+' requirements.txt | while IFS= read -r pkg; do
-            [ -n "$pkg" ] && python -m pip install --no-deps "$pkg" -c https://raw.githubusercontent.com/QuantStrategyLab/QuantPlatformKit/main/constraints.txt
-          done
+          python -m pip install -r requirements.txt
 
       - name: Resolve Cloud Run sync targets
         id: strategy_requirements