Add log ingestion tool for loading signature logs into SQLite

- Parse signature messages from log files extracting app info, device
  details, and feature flags (autofill, touchID, offline login, etc.)
- Support both plain .log and gzip compressed .log.gz files
- File discovery by date range (YYYY/mm/dd directory structure)
- Batch inserts for performance with large files (10GB+ per day)
- Index on session_id and version for efficient queries
- Extensible parser architecture via MessageParser trait
- Parallel file processing for multi-day ingestion

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

.github/workflows/audit.yaml

@@ -0,0 +1,31 @@
+name: Security audit
+
+on:
+  schedule:
+    - cron: "0 0 */3 * *"
+
+  push:
+    branches: [main]
+    paths:
+      - "**/Cargo.toml"
+      - "**/Cargo.lock"
+
+  pull_request:
+    paths:
+      - "**/Cargo.toml"
+      - "**/Cargo.lock"
+
+jobs:
+  audit:
+    name: Audit
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
+
+      - name: Install cargo-audit
+        uses: taiki-e/install-action@30eab0fabba9ea3f522099957e668b21876aa39e # v2.66.6
+        with:
+          tool: cargo-audit
+
+      - name: Run audit
+        run: cargo audit