Crash reports: replayable, bounded, local, reachable by agents (#384)

Every panic (in a command, in the kernel, anywhere else) and every unclean
exit (abort, stack overflow, kill) leaves a report in a local crash folder:
message, file:line, a trimmed backtrace, version, commit, system and renderer,
the command and recent commands, and when possible the design and replay.json
that reproduce it (solvecraft-cli crashes replay <id>).

- Cost: nothing until the app installs the hook (tests, CLI and web never
  do); then one small journal line per top-level command of the design on
  screen, taken back with a truncate when the command changed nothing.
- Unclean exits: each run holds a lock on its journal; a journal nobody holds
  at the next start belongs to an app that died. Autosaves restart the
  journal from the autosaved design.
- Bounded: a crash's signature (place + message, numbers ignored) is counted,
  not rewritten; at most 5 new reports per run, 20 reports, 50 MB, 90 days;
  recovered kernel panics are pruned first.
- Agents: diagnostics.crash_reports / crash_report / crash_reports.clear
  commands, the MCP crash_reports tool, solvecraft-cli crashes, solvecraft
  --crash-log; diagnostics.crash_test (with SOLVECRAFT_CRASH_TEST) checks it.
- People: the Crash Reports window opens after a crash (Help > Crash
  Reports…) with a reviewed issue draft per report; nothing is sent.
- Release builds keep line tables for file:line in backtraces.

Tests: child processes that really panic in a command, in the kernel, on a
thread, and abort; dedup counts, limits, hostile folders, journal parsing,
the UI window and draft, the MCP tool. docs/crash-reports.md.

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
Co-authored-by: bherbruck <brennen.herbruck@gmail.com>

crates/mcp/src/tests.rs

@@ -29,6 +29,18 @@ fn tool(s: &mut Server, name: &str, args: Value) -> Value {
     if c["type"] == "text" { serde_json::from_str(c["text"].as_str().unwrap()).unwrap_or(Value::Null) } else { c.clone() }
 }
 
+#[test]
+fn crash_reports_are_listed_and_read_without_changing_the_design() {
+    let mut s = server();
+    let list = tool(&mut s, "crash_reports", json!({"limit": 3}));
+    assert!(list["reports"].as_array().is_some_and(|r| r.len() <= 3), "{list}");
+    assert!(list["dir"].is_string(), "{list}");
+    let r = raw_tool(&mut s, "crash_reports", json!({"id": "../../etc"}));
+    assert_eq!(r["result"]["isError"], json!(true), "{r}");
+    let r = raw_tool(&mut s, "crash_reports", json!({"id": 5}));
+    assert!(r.get("error").is_some() || r["result"]["isError"] == json!(true), "{r}");
+}
+
 fn volume(s: &mut Server) -> f64 {
     tool(s, "measure", json!({}))["total"]["volume_mm3"].as_f64().unwrap()
 }
@@ -67,6 +79,7 @@ fn handshake_and_tools_list() {
         "export",
         "undo",
         "redo",
+        "crash_reports",
         "new_design",
         "open",
         "save",