feat: comprehensive security remediation - CodeQL fixes and best practices

Phase 1: Dependency Vulnerabilities
- Resolved 72/72 GitHub Dependabot vulnerabilities (100%)
- Updated cryptography, ecdsa, black, orjson, python-multipart

Phase 2: CodeQL Static Analysis (25+ categories)
- Fixed 100+ information exposure instances (str(e) → generic messages)
- Fixed 9 clear-text logging/storage instances
- Fixed 9 log injection instances (user data removed from logs)
- Fixed 2 hardcoded credential instances
- Fixed 15 print statements (replaced with logger)
- Added SSRF and path validation (18 alerts with robust validation)
- 20+ additional categories scanned (0 issues found)

Phase 3: CodeQL Infrastructure
- Created GitHub Actions CodeQL workflow
- Created CodeQL suppression file for false positives
- Moved CodeQL database to /var/lib/aitbc/codeql-db

Phase 4: Security Documentation
- Updated SECURITY_FIXES_SUMMARY.md with comprehensive details
- Documented security best practices for developers

Files modified: 48 files across coordinator-api, agent-services, blockchain-node, exchange, wallet, scripts, and infrastructure

codeql-custom-queries-python/codeql-pack.lock.yml

@@ -0,0 +1,30 @@
+---
+lockVersion: 1.0.0
+dependencies:
+  codeql/concepts:
+    version: 0.0.21
+  codeql/controlflow:
+    version: 2.0.31
+  codeql/dataflow:
+    version: 2.1.3
+  codeql/mad:
+    version: 1.0.47
+  codeql/python-all:
+    version: 7.0.4
+  codeql/regex:
+    version: 1.0.47
+  codeql/ssa:
+    version: 2.0.23
+  codeql/threat-models:
+    version: 1.0.47
+  codeql/tutorial:
+    version: 1.0.47
+  codeql/typetracking:
+    version: 2.0.31
+  codeql/util:
+    version: 2.0.34
+  codeql/xml:
+    version: 1.0.47
+  codeql/yaml:
+    version: 1.0.47
+compiled: false

codeql-custom-queries-python/codeql-pack.yml

@@ -0,0 +1,7 @@
+---
+library: false
+warnOnImplicitThis: false
+name: getting-started/codeql-extra-queries-python
+version: 1.0.0
+dependencies:
+  codeql/python-all: ^7.0.4

codeql-custom-queries-python/example.ql

@@ -0,0 +1,12 @@
+/**
+ * This is an automatically generated file
+ * @name Hello world
+ * @kind problem
+ * @problem.severity warning
+ * @id python/example/hello-world
+ */
+
+import python
+
+from File f
+select f, "Hello, world!"