Update operation logging spec to use single timestamp per tool call

openspec/changes/archive/2026-04-17-add-operation-logging/design.md

@@ -19,47 +19,27 @@
 
 | Pattern | Functions | How |
 |---------|------------|-----|
-| Streaming | MarkAllAsDeps, MarkAsExplicit, InstallAUR | `io.MultiWriter` to tee to both terminal and log |
-| Captured | SyncPackages, CleanupOrphans | capture with `CombinedOutput()`, write to log, write to terminal |
+| Captured | All state-modifying functions | capture output, write to log with single timestamp at start, write to terminal |
+
+### One Timestamp Per Tool Call
+Instead of streaming with MultiWriter (multiple timestamps), each state-modifying function:
+1. Writes timestamp + operation name to log
+2. Runs command, captures output
+3. Writes captured output to log
+4. Writes output to terminal
+
+This ensures exactly 1 timestamp print per tool call.
 
 ### Error Handling
 - Write error to log BEFORE returning from function
 - Print error to stderr so user sees it
 
 ### Dependencies
-- Add to imports: `io`, `os`, `path/filepath`
-
-### Structure
-
-```go
-// pkg/state/state.go
-var logFile *os.File
-
-func OpenLog() error {
-    logPath := filepath.Join("/var/log", "declpac.log")
-    f, err := os.OpenFile(logPath, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
-    if err != nil {
-        return err
-    }
-    logFile = f
-    return nil
-}
-
-func GetLogWriter() io.Writer {
-    return logFile
-}
-
-func Close() error {
-    if logFile == nil {
-        return nil
-    }
-    return logFile.Close()
-}
-```
+- Add to imports: `os`, `path/filepath`
 
 ### Flow in Sync() or main entrypoint
 1. Call `OpenLog()` at program start, defer close
-2. Each state-modifying function uses `state.GetLogWriter()` via MultiWriter
+2. Each state-modifying function calls `state.Write()` with timestamp prefix
 
 ### Wire into main.go
 - Open log at start of `run()`

openspec/changes/archive/2026-04-17-add-operation-logging/tasks.md

@@ -18,15 +18,11 @@ In `cmd/declpac/main.go` `run()`:
 
 Modify `pkg/pacman/pacman.go`:
 
-All state-modifying functions use `state.Write()` instead of `state.GetLogWriter().Write()`:
-
-```
-// OLD
-state.GetLogWriter().Write(output)
-
-// NEW
-state.Write(output)  // auto-prepends timestamp
-```
+Each state-modifying function writes timestamp ONCE at start, then captures output:
+- Write `timestamp - operation name` to log
+- Run command, capture output
+- Write captured output to log
+- Write output to terminal
 
 **Functions updated:**
 - `SyncPackages()` - write output with timestamp