feat: Use composite group/name key for monitor identification

Previously monitors were identified by just their name, causing monitors
with the same name in different groups to share data in the database.

Changes:
- Add ID() method to MonitorConfig returning 'group/name' format
- Add Group field to MonitorConfig (set at runtime)
- Update Monitor interface with ID() and Group() methods
- Update all monitor implementations (http, tcp, dns, icmp, gemini,
  graphql, database) to use composite ID
- Update Scheduler to use monitor ID instead of name
- Update server handlers to use composite ID for stats lookups
- Change API routes to use {group}/{name} pattern:
  - /api/monitor/{group}/{name}
  - /api/history/{group}/{name}
  - /api/uptime/{group}/{name}
  - /api/badge/{group}/{name}.svg
- URL-encode group and name components to handle special characters
  (e.g., slashes in names become %2F)
- Update config.UpdateResetFlag to accept group and name separately

BREAKING: API endpoints now require group in the path. Existing database
data using just monitor names won't be associated with the new composite
keys.

1 files changed, 15 insertions, 1 deletions

diff --git a/internal/monitor/database.go b/internal/monitor/database.go
index 0b4d2a9..3301632 100644
--- a/internal/monitor/database.go
+++ b/internal/monitor/database.go
@@ -14,7 +14,9 @@ import (
 
 // DatabaseMonitor monitors database connections
 type DatabaseMonitor struct {
+	id                string
 	name              string
+	group             string
 	target            string // Connection string or host:port
 	dbType            string // postgres, mysql, redis, mongodb, sqlite
 	interval          time.Duration
@@ -48,7 +50,9 @@ func NewDatabaseMonitor(cfg config.MonitorConfig) (*DatabaseMonitor, error) {
 	}
 
 	return &DatabaseMonitor{
+		id:                cfg.ID(),
 		name:              cfg.Name,
+		group:             cfg.Group,
 		target:            cfg.Target,
 		dbType:            dbType,
 		interval:          cfg.Interval.Duration,
@@ -59,11 +63,21 @@ func NewDatabaseMonitor(cfg config.MonitorConfig) (*DatabaseMonitor, error) {
 	}, nil
 }
 
+// ID returns the unique identifier for this monitor
+func (m *DatabaseMonitor) ID() string {
+	return m.id
+}
+
 // Name returns the monitor's name
 func (m *DatabaseMonitor) Name() string {
 	return m.name
 }
 
+// Group returns the group this monitor belongs to
+func (m *DatabaseMonitor) Group() string {
+	return m.group
+}
+
 // Type returns the monitor type
 func (m *DatabaseMonitor) Type() string {
 	return "database"
@@ -102,7 +116,7 @@ func (m *DatabaseMonitor) RoundUptime() bool {
 // Check performs the database connection check
 func (m *DatabaseMonitor) Check(ctx context.Context) *Result {
 	result := &Result{
-		MonitorName: m.name,
+		MonitorName: m.id,
 		Timestamp:   time.Now(),
 	}