fix(search): track appended scan ranges

CHANGELOG.md

@@ -22,6 +22,11 @@ for GitHub Release notes, so every published version must have a matching
   showing follow controls, while existing follow timelines retain append,
   detach, pause, and reset behavior.
 
+### Fixed
+
+- Keep forward and backward search sessions aware of committed records appended
+  after the search began, including when repeating a completed miss.
+
 ## [0.6.0] - 2026-07-22
 
 ### Added

README.md

@@ -274,10 +274,14 @@ committed tail:
 fmtview --follow service.jsonl
 ```
 
-The first frame reverse-scans only enough source data to build the last
-viewport; it does not format or index the file from the beginning. A final
-record is committed only after its newline arrives, so a writer's partial EOF
-record is never displayed early. While the viewport remains at the bottom,
+The first frame reverse-scans from EOF to the newest committed record boundary;
+that discovery work is proportional to the incomplete EOF suffix, so a
+newline-free file is the intentional worst case. It then loads the initial
+committed tail under a separate 128-record/4 MiB budget; one record may exceed
+the byte budget so it can remain intact. Earlier committed history is not
+formatted or indexed from the beginning. A final record is committed only after
+its newline arrives, so a writer's partial EOF record is never displayed early.
+While the viewport remains at the bottom,
 committed appends advance it automatically. Scrolling up changes the footer to
 `follow:detached`; scrolling back to the physical bottom reattaches. Press `f`
 to pause or resume follow explicitly. Search plus structure, chat-role, and tool
@@ -286,7 +290,11 @@ after opening.
 
 Follow mode requires a real file and an interactive stdout terminal. Ordinary
 viewing and redirected output are unchanged; `--follow` never turns redirected
-stdout into an endless stream.
+stdout into an endless stream. The built-in file source is intended for
+append-oriented logs and detects normal truncation, rotation, replacement, and
+copytruncate signals. A producer that performs arbitrary in-place rewrites
+without a distinguishable identity or metadata change should provide its own
+`RecordTimeline` implementation.
 
 ## Embedding a Record Timeline
 
@@ -617,9 +625,12 @@ rendered output in memory for browsing.
 - Record-like TTY previews, such as JSONL logs, use a lazy path: `fmtview`
   sniffs a small prefix to confirm that the input is independent records, then
   formats only the records needed for the visible window.
-- Follow-mode JSONL opens from a bounded reverse tail scan. Refresh locates the
+- Follow-mode JSONL opens from a chunked reverse tail scan. Refresh locates the
   newest committed delimiter from EOF, and record/byte budgets bound subsequent
-  older and newer loads; no persistent full-file index is required.
+  older and newer loads; no persistent full-file index is required. Committed
+  boundary discovery work is proportional to the incomplete EOF suffix. The
+  separate initial committed-tail load is capped at 128 records and 4 MiB,
+  except that one record may exceed the byte budget.
 - Lazy preview writes transformed records into a temporary spool and keeps compact
   offsets, not formatted strings, in memory. The title shows `N+` lines while
   the session index is still incomplete and idle time extends the index.

crates/fmtview-core/src/viewer/file.rs

@@ -420,6 +420,11 @@ impl FileViewer {
             self.state
                 .shift_for_insert(change.inserted_at, change.inserted_lines);
         }
+        if change.appended_lines > 0 {
+            let end = self.file.line_count();
+            self.state
+                .extend_for_append(end.saturating_sub(change.appended_lines), end);
+        }
         if change.appended_lines > 0 && self.state.follow == Some(FollowState::Following) {
             set_file_end(&mut self.state, self.file.line_count());
         }