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/rs/zerolog/encoder_json.go

@@ -0,0 +1,51 @@
+// +build !binary_log
+
+package zerolog
+
+// encoder_json.go file contains bindings to generate
+// JSON encoded byte stream.
+
+import (
+	"encoding/base64"
+	"github.com/rs/zerolog/internal/json"
+)
+
+var (
+	_ encoder = (*json.Encoder)(nil)
+
+	enc = json.Encoder{}
+)
+
+func init() {
+	// using closure to reflect the changes at runtime.
+	json.JSONMarshalFunc = func(v interface{}) ([]byte, error) {
+		return InterfaceMarshalFunc(v)
+	}
+}
+
+func appendJSON(dst []byte, j []byte) []byte {
+	return append(dst, j...)
+}
+func appendCBOR(dst []byte, cbor []byte) []byte {
+	dst = append(dst, []byte("\"data:application/cbor;base64,")...)
+	l := len(dst)
+	enc := base64.StdEncoding
+	n := enc.EncodedLen(len(cbor))
+	for i := 0; i < n; i++ {
+		dst = append(dst, '.')
+	}
+	enc.Encode(dst[l:], cbor)
+	return append(dst, '"')
+}
+
+func decodeIfBinaryToString(in []byte) string {
+	return string(in)
+}
+
+func decodeObjectToStr(in []byte) string {
+	return string(in)
+}
+
+func decodeIfBinaryToBytes(in []byte) []byte {
+	return in
+}