fix(ai): analyse the actual session, not stale/benign logs — 0.28.1

The user ran a game ~20s with no crash but the AI dredged up old log lines,
guessed the wrong game, and gave Windows advice. Fixes:
- Prompt now includes the real game name + capture duration + outcome (clean vs
  crash), so the model uses the known game instead of guessing from log paths.
- gamelogs.collect(since=…): scope Steam-console lines by timestamp and skip a
  stale per-app Proton log (mtime before the session) — no unrelated past run.
- ai_knowledge: flag benign Steam/Proton lines (libnvidia-ml.so.1 assertion,
  routine minidumps, "fork without exec") as non-causal.
- System prompt: Linux-only steps (no "run as administrator"); don't manufacture
  a problem on a clean run.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/rigdoctor/core/gamelogs.py

@@ -10,11 +10,41 @@ vkd3d/DXVK error, a crash line, the exit code) rather than only the sensor summa
 from __future__ import annotations
 
 import os
+import re
+import time
 from pathlib import Path
 
 # Steam keeps logs under its install root; ~/.steam/steam usually symlinks to the real one.
 _STEAM_LOG_DIRS = ("~/.steam/steam/logs", "~/.local/share/Steam/logs", "~/.steam/root/logs")
 _STEAM_LOG_FILES = ("console-linux.txt", "console_log.txt", "stderr.txt")
+_TS = re.compile(r"^\[(\d{4}-\d{2}-\d{2} \d{2}:\d{2}:\d{2})\]")
+
+
+def _line_epoch(line: str) -> float | None:
+    m = _TS.match(line)
+    if not m:
+        return None
+    try:
+        return time.mktime(time.strptime(m.group(1), "%Y-%m-%d %H:%M:%S"))
+    except ValueError:
+        return None
+
+
+def _since_filter(text: str, since: float) -> str:
+    """Keep lines from the first timestamp >= `since` onward (logs are chronological).
+
+    Untimestamped lines before the window are dropped; once inside the window every line is
+    kept (so multi-line entries survive). This scopes a long-lived Steam log to one session.
+    """
+    out: list[str] = []
+    including = False
+    for line in text.splitlines():
+        epoch = _line_epoch(line)
+        if epoch is not None and epoch >= since:
+            including = True
+        if including:
+            out.append(line)
+    return "\n".join(out)
 
 
 def _tail(path: Path, max_bytes: int) -> str:
@@ -51,17 +81,36 @@ def available() -> bool:
     return bool(_proton_logs() or _steam_console())
 
 
-def collect(max_bytes: int = 6000) -> str:
-    """Recent Proton + Steam log tails as one labelled text block ('' if none)."""
+def collect(since: float | None = None, max_bytes: int = 8000) -> str:
+    """Recent Proton + Steam log tails as one labelled text block ('' if none).
+
+    With ``since`` (epoch), scope to that session: skip a Proton log not written during/after
+    the session (a stale per-app log from an earlier game), and keep only Steam-console lines
+    timestamped at/after ``since`` — so we don't feed the model an unrelated past session.
+    """
     sections: list[str] = []
+
     protons = _proton_logs()
     if protons:
-        tail = _tail(protons[0], max_bytes).strip()
+        log = protons[0]
+        fresh = since is None or _mtime(log) >= since
+        tail = _tail(log, max_bytes).strip() if fresh else ""
         if tail:
-            sections.append(f"--- Proton log ({protons[0].name}) ---\n{tail}")
+            sections.append(f"--- Proton log ({log.name}) ---\n{tail}")
+
     console = _steam_console()
     if console:
-        tail = _tail(console, max_bytes).strip()
-        if tail:
-            sections.append(f"--- Steam log ({console.name}) ---\n{tail}")
+        raw = _tail(console, 40000 if since else max_bytes)
+        if since is not None:
+            raw = _since_filter(raw, since)
+        raw = raw.strip()[-max_bytes:].strip()
+        if raw:
+            sections.append(f"--- Steam log ({console.name}) ---\n{raw}")
     return "\n\n".join(sections)
+
+
+def _mtime(path: Path) -> float:
+    try:
+        return path.stat().st_mtime
+    except OSError:
+        return 0.0