[Autoloop: python-to-go-migration] Iteration 45: migrate core/token_manager (+497), primitives/discovery (+612)

Migrated 2 modules, +1109 Python lines. Metric: 38.91 -> 40.45 (+1.54).

- core/token_manager: GitHubTokenManager with credential-fill subprocess, gh CLI fallback,
  per-(host,port) cache, and setup/validate helpers for Copilot/Codex/LLM runtimes.
- primitives/discovery: PrimitiveCollection with conflict detection, local/dependency
  primitive scanning, globMatch with ** support, FindPrimitiveFiles with exclude pruning.

Run: https://github.com/githubnext/apm/actions/runs/25871294987

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: github-actions[bot]

benchmarks/migration-status.json

@@ -1,6 +1,6 @@
 {
   "original_python_lines": 71696,
-  "migrated_python_lines": 27894,
+  "migrated_python_lines": 29003,
   "migrated_modules": [
     {
       "module": "src/apm_cli/constants.py",
@@ -794,9 +794,9 @@
       "notes": "LLM CLI runtime adapter"
     }
   ],
-  "last_updated": "2026-05-14T12:17:24Z",
-  "iteration": 43,
-  "python_lines_migrated_pct": 38.06,
+  "last_updated": "2026-05-14T16:23:30Z",
+  "iteration": 44,
+  "python_lines_migrated_pct": 40.45,
   "modules_migrated": 106,
   "modules": [
     {
@@ -831,6 +831,18 @@
       "python_lines": 775,
       "go_package": "internal/integration/commandintegrator",
       "status": "migrated"
+    },
+    {
+      "module": "core/token_manager",
+      "status": "migrated",
+      "python_lines": 497,
+      "go_package": "internal/core/tokenmanager"
+    },
+    {
+      "module": "primitives/discovery",
+      "status": "migrated",
+      "python_lines": 612,
+      "go_package": "internal/primitives/discovery"
     }
   ]
 }

internal/core/tokenmanager/timer.go

@@ -0,0 +1,13 @@
+package tokenmanager
+
+import "time"
+
+// timerAfter returns a channel that closes after n seconds.
+func timerAfter(n int) <-chan struct{} {
+	ch := make(chan struct{})
+	go func() {
+		time.Sleep(time.Duration(n) * time.Second)
+		close(ch)
+	}()
+	return ch
+}