Fix lints surfaced by Rust 1.98.1 under -D warnings

CI compiles with RUSTFLAGS="-D warnings", so lints added since 1.85.0
fail the build:

- mismatched_lifetime_syntaxes (new in 1.89): eleven signatures elide a
  lifetime on the input side (&self / &str) but hide it on the output type
  (Vec<Column>, PageHdrIter, CursorStep<S>, Cow<str>). Spell the output
  lifetime as '_ as the compiler suggests. No semantic change; this is the
  lifetime rustc already inferred.
- unused_assignments: `frameno` in bottomless-cli's restore loop was only
  ever copied into BatchReader::new and then incremented, never read.
  BatchReader tracks its own next_frame_no and the function returns the
  separate last_received_frame_no, so the local was dead since it was
  introduced in 4a71b20. Remove it and pass first_frame_no directly.

Verified locally on 1.98.1 with the same flags as CI:
cargo check --all-targets --all-features, cargo fmt --check, and
cargo check -p libsql --no-default-features for core/replication/remote.

Author: AryanSuvarna

bottomless-cli/src/replicator_extras.rs

@@ -382,9 +382,8 @@ impl Replicator {
             let frame = tokio::fs::File::open(&obj).await?;
             let frame_buf_reader = BufReader::new(frame);
 
-            let mut frameno = first_frame_no;
             let mut reader = bottomless::read::BatchReader::new(
-                frameno,
+                first_frame_no,
                 frame_buf_reader,
                 page_size as usize,
                 compression_kind,
@@ -411,7 +410,6 @@ impl Replicator {
                     );
                     pending_pages.flush(db).await?;
                 }
-                frameno += 1;
                 last_received_frame_no += 1;
             }
             db.flush().await?;

libsql-server/src/query_analysis.rs

@@ -233,7 +233,7 @@ impl StmtKind {
     }
 }
 
-fn to_ascii_lower(s: &str) -> Cow<str> {
+fn to_ascii_lower(s: &str) -> Cow<'_, str> {
     if s.chars().all(|c| char::is_ascii_lowercase(&c)) {
         Cow::Borrowed(s)
     } else {

libsql-sys/src/wal/mod.rs

@@ -131,7 +131,7 @@ impl PageHeaders {
         Self { inner }
     }
 
-    pub fn iter(&self) -> PageHdrIter {
+    pub fn iter(&self) -> PageHdrIter<'_> {
         // TODO: move LIBSQL_PAGE_SIZE
         PageHdrIter::new(self.as_ptr(), 4096)
     }

libsql/src/hrana/cursor.rs

@@ -147,7 +147,7 @@ where
         })
     }
 
-    pub async fn next_step(&mut self) -> Result<CursorStep<S>> {
+    pub async fn next_step(&mut self) -> Result<CursorStep<'_, S>> {
         CursorStep::new(self).await
     }
 

libsql/src/hrana/hyper.rs

@@ -276,7 +276,7 @@ impl crate::statement::Stmt for crate::hrana::Statement<HttpSender> {
         self.cols.len()
     }
 
-    fn columns(&self) -> Vec<crate::Column> {
+    fn columns(&self) -> Vec<crate::Column<'_>> {
         //FIXME: there are several blockers here:
         // 1. We cannot know the column types before sending a query, so this method will never return results right
         //    away.

libsql/src/local/impls.rs

@@ -160,7 +160,7 @@ impl Stmt for LibsqlStmt {
         self.0.column_count()
     }
 
-    fn columns(&self) -> Vec<Column> {
+    fn columns(&self) -> Vec<Column<'_>> {
         self.0.columns()
     }
 }

libsql/src/local/statement.rs

@@ -339,7 +339,7 @@ impl Statement {
     /// If associated DB schema can be altered concurrently, you should make
     /// sure that current statement has already been stepped once before
     /// calling this method.
-    pub fn columns(&self) -> Vec<Column> {
+    pub fn columns(&self) -> Vec<Column<'_>> {
         let n = self.column_count();
         let mut cols = Vec::with_capacity(n);
         for i in 0..n {

libsql/src/replication/connection.rs

@@ -797,7 +797,7 @@ impl Stmt for RemoteStatement {
         }
     }
 
-    fn columns(&self) -> Vec<Column> {
+    fn columns(&self) -> Vec<Column<'_>> {
         if let Some(stmt) = self.local_statement.as_ref() {
             return stmt.columns();
         }

libsql/src/statement.rs

@@ -24,7 +24,7 @@ pub(crate) trait Stmt {
 
     fn column_count(&self) -> usize;
 
-    fn columns(&self) -> Vec<Column>;
+    fn columns(&self) -> Vec<Column<'_>>;
 }
 
 /// A cached prepared statement.
@@ -103,7 +103,7 @@ impl Statement {
     }
 
     /// Fetch the list of columns for the prepared statement.
-    pub fn columns(&self) -> Vec<Column> {
+    pub fn columns(&self) -> Vec<Column<'_>> {
         self.inner.columns()
     }
 }

libsql/src/sync/statement.rs

@@ -67,7 +67,7 @@ impl Stmt for SyncedStatement {
         self.inner.column_count()
     }
 
-    fn columns(&self) -> Vec<Column> {
+    fn columns(&self) -> Vec<Column<'_>> {
         self.inner.columns()
     }
 }