feat: Production readiness improvements for WHOOSH council formation

Major security, observability, and configuration improvements:

## Security Hardening
- Implemented configurable CORS (no more wildcards)
- Added comprehensive auth middleware for admin endpoints
- Enhanced webhook HMAC validation
- Added input validation and rate limiting
- Security headers and CSP policies

## Configuration Management
- Made N8N webhook URL configurable (WHOOSH_N8N_BASE_URL)
- Replaced all hardcoded endpoints with environment variables
- Added feature flags for LLM vs heuristic composition
- Gitea fetch hardening with EAGER_FILTER and FULL_RESCAN options

## API Completeness
- Implemented GetCouncilComposition function
- Added GET /api/v1/councils/{id} endpoint
- Council artifacts API (POST/GET /api/v1/councils/{id}/artifacts)
- /admin/health/details endpoint with component status
- Database lookup for repository URLs (no hardcoded fallbacks)

## Observability & Performance
- Added OpenTelemetry distributed tracing with goal/pulse correlation
- Performance optimization database indexes
- Comprehensive health monitoring
- Enhanced logging and error handling

## Infrastructure
- Production-ready P2P discovery (replaces mock implementation)
- Removed unused Redis configuration
- Enhanced Docker Swarm integration
- Added migration files for performance indexes

## Code Quality
- Comprehensive input validation
- Graceful error handling and failsafe fallbacks
- Backwards compatibility maintained
- Following security best practices

🤖 Generated with [Claude Code](https://claude.ai/code)

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

vendor/github.com/jackc/puddle/v2/log.go

@@ -0,0 +1,32 @@
+package puddle
+
+import "unsafe"
+
+type ints interface {
+	int | int8 | int16 | int32 | int64 | uint | uint8 | uint16 | uint32 | uint64
+}
+
+// log2Int returns log2 of an integer. This function panics if val < 0. For val
+// == 0, returns 0.
+func log2Int[T ints](val T) uint8 {
+	if val <= 0 {
+		panic("log2 of non-positive number does not exist")
+	}
+
+	return log2IntRange(val, 0, uint8(8*unsafe.Sizeof(val)))
+}
+
+func log2IntRange[T ints](val T, begin, end uint8) uint8 {
+	length := end - begin
+	if length == 1 {
+		return begin
+	}
+
+	delim := begin + length/2
+	mask := T(1) << delim
+	if mask > val {
+		return log2IntRange(val, begin, delim)
+	} else {
+		return log2IntRange(val, delim, end)
+	}
+}