feat(01-01): implement FindClaudeProcesses and EncodePath

- Scan /proc for PIDs with "claude" in cmdline
- Read cwd via os.Readlink, skip errors silently
- EncodePath replaces / and . with - for ~/.claude/projects/ folder names

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

proc.go

@@ -0,0 +1,62 @@
+package main
+
+import (
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+)
+
+// FindClaudeProcesses scans procDir (typically "/proc") for active Claude Code processes.
+// It returns a Process for each PID whose cmdline starts with "claude".
+// Read errors (permission denied, vanished process) are silently skipped.
+func FindClaudeProcesses(procDir string) ([]Process, error) {
+	entries, err := os.ReadDir(procDir)
+	if err != nil {
+		return nil, err
+	}
+
+	var procs []Process
+
+	for _, entry := range entries {
+		pid, err := strconv.Atoi(entry.Name())
+		if err != nil {
+			continue // not a PID directory
+		}
+
+		cmdlineData, err := os.ReadFile(filepath.Join(procDir, entry.Name(), "cmdline"))
+		if err != nil {
+			continue // permission denied or process vanished
+		}
+
+		parts := strings.Split(strings.TrimRight(string(cmdlineData), "\x00"), "\x00")
+		if len(parts) == 0 {
+			continue
+		}
+
+		// Match if the binary name ends with "claude" or is exactly "claude"
+		bin := filepath.Base(parts[0])
+		if bin != "claude" {
+			continue
+		}
+
+		cwd, err := os.Readlink(filepath.Join(procDir, entry.Name(), "cwd"))
+		if err != nil {
+			continue // cannot read cwd
+		}
+
+		procs = append(procs, Process{
+			PID: pid,
+			Cmd: parts,
+			Cwd: cwd,
+		})
+	}
+
+	return procs, nil
+}
+
+// EncodePath converts an absolute path to the folder name format used by
+// ~/.claude/projects/. Slashes and dots are replaced with dashes.
+func EncodePath(path string) string {
+	return strings.NewReplacer("/", "-", ".", "-").Replace(path)
+}