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/nats-io/nkeys/creds_utils.go

@@ -0,0 +1,78 @@
+package nkeys
+
+import (
+	"bytes"
+	"regexp"
+	"strings"
+)
+
+var userConfigRE = regexp.MustCompile(`\s*(?:(?:[-]{3,}.*[-]{3,}\r?\n)([\w\-.=]+)(?:\r?\n[-]{3,}.*[-]{3,}\r?\n))`)
+
+// ParseDecoratedJWT takes a creds file and returns the JWT portion.
+func ParseDecoratedJWT(contents []byte) (string, error) {
+	items := userConfigRE.FindAllSubmatch(contents, -1)
+	if len(items) == 0 {
+		return string(contents), nil
+	}
+	// First result should be the user JWT.
+	// We copy here so that if the file contained a seed file too we wipe appropriately.
+	raw := items[0][1]
+	tmp := make([]byte, len(raw))
+	copy(tmp, raw)
+	return strings.TrimSpace(string(tmp)), nil
+}
+
+// ParseDecoratedNKey takes a creds file, finds the NKey portion and creates a
+// key pair from it.
+func ParseDecoratedNKey(contents []byte) (KeyPair, error) {
+	var seed []byte
+
+	items := userConfigRE.FindAllSubmatch(contents, -1)
+	if len(items) > 1 {
+		seed = items[1][1]
+	} else {
+		lines := bytes.Split(contents, []byte("\n"))
+		for _, line := range lines {
+			if bytes.HasPrefix(bytes.TrimSpace(line), []byte("SO")) ||
+				bytes.HasPrefix(bytes.TrimSpace(line), []byte("SA")) ||
+				bytes.HasPrefix(bytes.TrimSpace(line), []byte("SU")) {
+				seed = line
+				break
+			}
+		}
+	}
+	if seed == nil {
+		return nil, ErrNoSeedFound
+	}
+	if !bytes.HasPrefix(seed, []byte("SO")) &&
+		!bytes.HasPrefix(seed, []byte("SA")) &&
+		!bytes.HasPrefix(seed, []byte("SU")) {
+		return nil, ErrInvalidNkeySeed
+	}
+	kp, err := FromSeed(seed)
+	if err != nil {
+		return nil, err
+	}
+	return kp, nil
+}
+
+// ParseDecoratedUserNKey takes a creds file, finds the NKey portion and creates a
+// key pair from it. Similar to ParseDecoratedNKey but fails for non-user keys.
+func ParseDecoratedUserNKey(contents []byte) (KeyPair, error) {
+	nk, err := ParseDecoratedNKey(contents)
+	if err != nil {
+		return nil, err
+	}
+	seed, err := nk.Seed()
+	if err != nil {
+		return nil, err
+	}
+	if !bytes.HasPrefix(seed, []byte("SU")) {
+		return nil, ErrInvalidUserSeed
+	}
+	kp, err := FromSeed(seed)
+	if err != nil {
+		return nil, err
+	}
+	return kp, nil
+}