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/golang-migrate/migrate/v4/database/multistmt/parse.go

@@ -0,0 +1,46 @@
+// Package multistmt provides methods for parsing multi-statement database migrations
+package multistmt
+
+import (
+	"bufio"
+	"bytes"
+	"io"
+)
+
+// StartBufSize is the default starting size of the buffer used to scan and parse multi-statement migrations
+var StartBufSize = 4096
+
+// Handler handles a single migration parsed from a multi-statement migration.
+// It's given the single migration to handle and returns whether or not further statements
+// from the multi-statement migration should be parsed and handled.
+type Handler func(migration []byte) bool
+
+func splitWithDelimiter(delimiter []byte) func(d []byte, atEOF bool) (int, []byte, error) {
+	return func(d []byte, atEOF bool) (int, []byte, error) {
+		// SplitFunc inspired by bufio.ScanLines() implementation
+		if atEOF {
+			if len(d) == 0 {
+				return 0, nil, nil
+			}
+			return len(d), d, nil
+		}
+		if i := bytes.Index(d, delimiter); i >= 0 {
+			return i + len(delimiter), d[:i+len(delimiter)], nil
+		}
+		return 0, nil, nil
+	}
+}
+
+// Parse parses the given multi-statement migration
+func Parse(reader io.Reader, delimiter []byte, maxMigrationSize int, h Handler) error {
+	scanner := bufio.NewScanner(reader)
+	scanner.Buffer(make([]byte, 0, StartBufSize), maxMigrationSize)
+	scanner.Split(splitWithDelimiter(delimiter))
+	for scanner.Scan() {
+		cont := h(scanner.Bytes())
+		if !cont {
+			break
+		}
+	}
+	return scanner.Err()
+}