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/tools.rs

@@ -183,6 +183,24 @@ pub fn tool_definitions() -> Vec<Value> {
             false,
             false,
         ),
+        tool(
+            "crash_reports",
+            "Crash reports",
+            "SolidCraft's crash reports on this computer (the app's when connected to it). Without `id`: the list, newest \
+             first (id, kind, time, message, command, count, version, path, replayable). With `id`: the whole report: \
+             message, location, backtrace, app version and commit, system, the command that crashed and the recent ones, \
+             and design_path / replay_path when it can be replayed: `solidcraft-cli crashes replay <id>`, or \
+             `solidcraft-cli run <replay_path> --in <design_path>`. Reports never leave this computer.",
+            obj(
+                json!({
+                    "id": string("A report id from the list"),
+                    "limit": {"type": "integer", "description": "Reports to list (default 20)"},
+                }),
+                &[],
+            ),
+            true,
+            false,
+        ),
         tool("undo", "Undo", "Undo the last change to the design.", obj(json!({}), &[]), false, false),
         tool("redo", "Redo", "Redo the last undone change.", obj(json!({}), &[]), false, false),
         tool(
@@ -352,6 +370,10 @@ fn dispatch(b: &mut dyn Backend, name: &str, a: &Map<String, Value>) -> Result<V
             exec(b, "parameters.change", p)
         }
         "export" => exec(b, "file.export", pick(a, &["path", "format", "bodies"])),
+        "crash_reports" => match a.get("id") {
+            Some(_) => exec(b, "diagnostics.crash_report", pick(a, &["id"])),
+            None => exec(b, "diagnostics.crash_reports", pick(a, &["limit"])),
+        },
         "undo" => exec(b, "edit.undo", json!({})),
         "redo" => exec(b, "edit.redo", json!({})),
         "new_design" => exec(b, "file.new", pick(a, &["name"])),