feat: collect timeout timing sessions for diagnostics (#814)

docs/CONFIGURATION.md

@@ -262,6 +262,7 @@ diagnostics:
     publish: false             # Capture screenshot + HTML + JSON on each failed publish attempt (timeouts/protocol errors)
   capture_log_copy: false       # Copy entire bot log file when diagnostics are captured (may duplicate log content)
   pause_on_login_detection_failure: false  # Pause for manual inspection (interactive only)
+  timing_collection: true       # Collect timeout timing data locally for troubleshooting and tuning
   output_dir: ""               # Custom output directory (see "Output locations (default)" below)
 ```
 
@@ -309,7 +310,44 @@ The bot uses a layered approach to detect login state, prioritizing stealth over
 - **User directories mode**: `~/.cache/kleinanzeigen-bot/diagnostics/` (Linux), `~/Library/Caches/kleinanzeigen-bot/diagnostics/` (macOS), or `%LOCALAPPDATA%\kleinanzeigen-bot\Cache\diagnostics\` (Windows)
 - **Custom**: Path resolved relative to your `config.yaml` if `output_dir` is specified
 
-> **⚠️ PII Warning:** HTML dumps, JSON payloads, and log copies may contain PII. Typical examples include account email, ad titles/descriptions, contact info, and prices. Log copies are produced by `capture_log_copy` when diagnostics capture runs, such as `capture_on.publish` or `capture_on.login_detection`. Review or redact these artifacts before sharing them publicly.
+**Timing collection output (default):**
+
+- **Portable mode**: `./.temp/timing/timing_data.json`
+- **User directories mode**: `~/.cache/kleinanzeigen-bot/timing/timing_data.json` (Linux) or `~/Library/Caches/kleinanzeigen-bot/timing/timing_data.json` (macOS)
+- Data is grouped by run/session and retained for 30 days via automatic cleanup during each data write
+
+Example structure:
+
+```json
+[
+  {
+    "session_id": "abc12345",
+    "command": "publish",
+    "started_at": "2026-02-07T10:00:00+01:00",
+    "ended_at": "2026-02-07T10:04:30+01:00",
+    "records": [
+      {
+        "operation_key": "default",
+        "operation_type": "web_find",
+        "effective_timeout_sec": 5.0,
+        "actual_duration_sec": 1.2,
+        "attempt_index": 0,
+        "success": true
+      }
+    ]
+  }
+]
+```
+
+How to read it quickly:
+
+- Group by `command` and `session_id` first to compare slow vs fast runs
+- Look for high `actual_duration_sec` values near `effective_timeout_sec` and repeated `success: false` entries
+- `attempt_index` is zero-based (`0` first attempt, `1` first retry)
+- Use `operation_key` + `operation_type` to identify which timeout bucket (`default`, `page_load`, etc.) needs tuning
+- For deeper timeout tuning workflow, see [Browser Troubleshooting](./BROWSER_TROUBLESHOOTING.md)
+
+> **⚠️ PII Warning:** HTML dumps, JSON payloads, timing data JSON files (for example `timing_data.json`), and log copies may contain PII. Typical examples include account email, ad titles/descriptions, contact info, and prices. Log copies are produced by `capture_log_copy` when diagnostics capture runs, such as `capture_on.publish` or `capture_on.login_detection`. Review or redact these artifacts before sharing them publicly.
 
 ## Installation Modes