feat: weekly progress update system for TurboQuant (#76)

- scripts/weekly_update.py: Auto-generates weekly update from git log,
  Gitea API (issues/PRs/blockers), and benchmark results. Supports
  --post to issue #76, --json for raw data, --since for date range.
- scripts/weekly_update.sh: Shell wrapper for convenience.
- docs/WEEKLY_TEMPLATE.md: Manual update template.
- docs/PROJECT_STATUS.md: Added Weekly Progress Updates section with
  process (weekly cadence, benchmark-as-happens, blocker escalation).
- tests/test_weekly_update.py: Validates script runs, JSON output,
  and handles edge cases.

docs/WEEKLY_TEMPLATE.md

@@ -0,0 +1,26 @@
+# TurboQuant Weekly Update Template
+
+Use this template when posting manual weekly updates. For automated updates, run `scripts/weekly_update.py --post`.
+
+## Week of [START_DATE] to [END_DATE]
+
+### Completed
+- [item 1]
+- [item 2]
+
+### Benchmark Results
+- [key metric or "No new benchmarks this week"]
+
+### In Progress
+- [item being worked on — who's on it]
+
+### Blockers
+- [blocker — impact — who needs to act]
+- _None_ if clear
+
+### Next Week
+- [planned item 1]
+- [planned item 2]
+
+---
+_Generated by `scripts/weekly_update.py` or filled manually._