refactor!: rebrand CCAM to AgentHub

Clean break, no compatibility alias. Renames the product name, the CLI
binary (`ccam` -> `agenthub`), the env var prefix (`CCAM_` ->
`AGENTHUB_`), the Prometheus metric namespace (`ccam_*` ->
`agenthub_*`), the tmux session prefix (`ccam-lane-<id>` ->
`agenthub-lane-<id>`), the per-repo runtime profile directory
(`.ccam/profile` -> `.agenthub/profile`), the lanes state root
(`~/.claude/ccam-lanes` -> `~/.claude/agenthub-lanes`), the bundled
plugins (`plugins/ccam*` -> `plugins/agenthub*`) and their slash
commands (`/ccam-doctor` -> `/agenthub-doctor`, `/ccam:*` ->
`/agenthub:*`).

Because there is no alias, an existing install has to be updated by
hand: rename its `.ccam/profile` directory and any `CCAM_*` variables,
and reinstall the plugin under its new name.

Two other name families are deliberately left alone here, since they are
not just strings: the `Claude-Code-Monitor` repository/marketplace name,
and the `agent-dashboard` npm package plus its `~/.claude/agent-dashboard`
runtime directory, which holds the live database and needs a migration
rather than a rename.

Verified: server 1406/1406, client 459/459, `grep -i ccam` clean across
tracked files, `openapi.yaml` regenerated (95 paths, unchanged count).

server/lib/webhook-providers.js

@@ -85,7 +85,7 @@ function formatDiscord(alert) {
         description: truncate(alert.message, 4000),
         color: ACCENT_INT,
         fields,
-        footer: { text: "Claude Code Agent Monitor" },
+        footer: { text: "AgentHub" },
         timestamp: alert.triggered_at,
       },
     ],
@@ -152,7 +152,7 @@ function formatMattermost(alert) {
         color: ACCENT_HEX,
         text: truncate(alert.message, 3000),
         fields: attachmentFields(alert),
-        footer: "Claude Code Agent Monitor",
+        footer: "AgentHub",
       },
     ],
   };
@@ -196,7 +196,7 @@ function formatPagerDuty(alert, config) {
   return {
     routing_key: config.routing_key,
     event_action: "trigger",
-    dedup_key: `ccam:${alert.rule_id || "test"}:${alert.session_id || ""}`,
+    dedup_key: `agenthub:${alert.rule_id || "test"}:${alert.session_id || ""}`,
     payload: {
       summary: truncate(`${alert.rule_name}: ${alert.message}`, 1024),
       source: alert.session_id || "claude-code-agent-monitor",
@@ -219,7 +219,7 @@ function formatPagerDuty(alert, config) {
 function formatOpsgenie(alert) {
   return {
     message: truncate(`${alert.rule_name}: ${alert.message}`, 130),
-    alias: `ccam:${alert.rule_id || "test"}:${alert.session_id || ""}`,
+    alias: `agenthub:${alert.rule_id || "test"}:${alert.session_id || ""}`,
     description: truncate(alert.message, 15000),
     source: "claude-code-agent-monitor",
     tags: ["claude-code", alert.rule_type].filter(Boolean),
@@ -238,7 +238,7 @@ function formatOpsgenie(alert) {
 function formatSplunkOnCall(alert, config) {
   return {
     message_type: config.severity || "WARNING",
-    entity_id: `ccam:${alert.rule_id || "test"}:${alert.session_id || ""}`,
+    entity_id: `agenthub:${alert.rule_id || "test"}:${alert.session_id || ""}`,
     entity_display_name: truncate(alert.rule_name, 256),
     state_message: truncate(
       `${alert.message}\n\ntype: ${alert.rule_type}${alert.session_id ? `\nsession: ${alert.session_id}` : ""}`,