[raiseCatError]

Stacked on #533.

Bug (found in headless acceptance QA of /changes; repro iso/retention.mjs): above 200 entries, the journal prunes oldest first. It kept only the newest 20 reset/restore/manual entries and the newest entry per (source, path). So two appearance edits of kitty.conf followed by 260 automatic cursor-shader writes pruned the first kitty.conf backup, the only copy of the user's config from before NMSh touched it. On the maintainer's real machine NMSh wrote 16 cursor-shader backups in about 75 s, so 200 entries is roughly 15 minutes of such activity.

Fix (src/backups/journal.ts): the oldest entry of every file path is pruned only as a last resort, after every unprotected entry has gone. Existing guarantees are unchanged, including the tiny-cap case in "the newest source/path anchor is retained…".

Tests

• New: tests/backupsJournal.test.ts "a burst of automatic writes to another file never prunes the original backup…". It fails without the fix and passes with it.
• backupsJournal, backupsRestore, backupsPanels: 45/45.
• configurationPersistence, shellFrameworks, starshipConfigAdapter: 26/26.
• tsc is clean.
• Repro at the real cap (200): before the fix only the second appearance backup was kept; now both are.

Other findings from the same QA, not fixed here (follow-ups):

• D2: theme-bridge/ledger.json is rewritten on every launch without a backup, so most entries show "edited since". Restoring an older entry reverts the ledger and drops vim ownership.
• D3: one unreadable recorded path (a directory replaced by a file) makes every later config write fail ("A configuration parent is not a directory"), and /changes names neither the entry nor the cause.
• D4: an entry left prepared by a killed write is not flagged as interrupted.
• D5: labels like "appends 2 lines at the end" or "1 files" name no tool or file.
• D6: a reset records two near-duplicate entries, and the footer says "Enter confirm write" on steps that only advance.
• D7: "NMSh settings → defaults" also resets onboarding flags and sets updateMode to automatic.