feat: ADR-0034 — history journal records err + replay parses/filters the journal

Replay (§3): run_replay parses <ts>|<status>|<source> journal records — runs ok, skips non-ok — while still accepting bare .commands scripts (prefix-detected so a | inside a bare command isn't misread). Fixes replay history.log, which died on line 1.

Journal failures (§1/§2): failed commands are recorded err via a new Action::JournalFailure, emitted by the pure-sync App for both parse failures and worker-execution failures (runtime appends best-effort, never fatal). Hydration reads all records so typo'd/rejected commands are recallable across sessions.

Amendment 1 — replay filters app-lifecycle commands: a working replay history.log exposed that the journal also records save as/load/new/export/import/rebuild/mode (which would panic the worker dispatch or abort replay). Replay now re-applies only schema/data writes and skips every app-lifecycle command + nested replay, classified by entry word so modal/incomplete forms (save as, bare mode) and quit skip uniformly rather than aborting. All skips continue (reversing the nested-replay refusal); import and nested replay warn. replay.error_nested removed; replay.skipped_import/_replay added; ReplayCompleted carries warnings. requirements.md U3/U4 updated; app-command runtime-failure journalling tracked as a follow-up.

1659 passing / 0 failing / 0 skipped / 1 ignored. Clippy clean.

tests/iteration5_export_import.rs

@@ -182,8 +182,13 @@ fn import_with_empty_target_after_as_errors() {
     let actions = submit(&mut app);
     // "as " trailing whitespace is trimmed by .split_once + .trim,
     // making the as-target empty. We surface this as a usage
-    // error rather than silently importing without a target.
-    assert!(actions.is_empty());
+    // error rather than silently importing without a target. The
+    // failed line is journalled `err` (ADR-0034) but no import
+    // dispatches.
+    assert!(
+        matches!(actions.as_slice(), [Action::JournalFailure { .. }]),
+        "expected only a JournalFailure, no import dispatch; got {actions:?}",
+    );
     // The friendly parse-error rendering produces multiple
     // output lines (caret, message, usage). Scan for the anchor
     // phrase rather than asserting on the final line. The