clock: Cleanup ReplicaId, Lamport and Global (#40600)

- Notable change is the use of a newtype for `ReplicaId`
- Fixes `WorktreeStore::create_remote_worktree` creating a remote
worktree with the local replica id, though this is not currently used
- Fixes observing the `Agent` (that is following the agent) causing
global clocks to allocate 65535 elements
- Shrinks the size of `Global` a bit. In a local or non-collab remote
session it won't ever allocate still.

Release Notes:

- N/A *or* Added/Fixed/Improved ...

crates/text/src/text.rs

@@ -12,7 +12,7 @@ mod undo_map;
 
 pub use anchor::*;
 use anyhow::{Context as _, Result};
-use clock::LOCAL_BRANCH_REPLICA_ID;
+use clock::Lamport;
 pub use clock::ReplicaId;
 use collections::{HashMap, HashSet};
 use locator::Locator;
@@ -573,7 +573,7 @@ struct InsertionFragment {
     fragment_id: Locator,
 }
 
-#[derive(Clone, Copy, Debug, Default, PartialEq, Eq, PartialOrd, Ord)]
+#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord)]
 struct InsertionFragmentKey {
     timestamp: clock::Lamport,
     split_offset: usize,
@@ -709,7 +709,7 @@ impl FromIterator<char> for LineIndent {
 }
 
 impl Buffer {
-    pub fn new(replica_id: u16, remote_id: BufferId, base_text: impl Into<String>) -> Buffer {
+    pub fn new(replica_id: ReplicaId, remote_id: BufferId, base_text: impl Into<String>) -> Buffer {
         let mut base_text = base_text.into();
         let line_ending = LineEnding::detect(&base_text);
         LineEnding::normalize(&mut base_text);
@@ -717,7 +717,7 @@ impl Buffer {
     }
 
     pub fn new_normalized(
-        replica_id: u16,
+        replica_id: ReplicaId,
         remote_id: BufferId,
         line_ending: LineEnding,
         normalized: Rope,
@@ -731,10 +731,7 @@ impl Buffer {
 
         let visible_text = history.base_text.clone();
         if !visible_text.is_empty() {
-            let insertion_timestamp = clock::Lamport {
-                replica_id: 0,
-                value: 1,
-            };
+            let insertion_timestamp = clock::Lamport::new(ReplicaId::LOCAL);
             lamport_clock.observe(insertion_timestamp);
             version.observe(insertion_timestamp);
             let fragment_id = Locator::between(&Locator::min(), &Locator::max());
@@ -788,7 +785,7 @@ impl Buffer {
             history: History::new(self.base_text().clone()),
             deferred_ops: OperationQueue::new(),
             deferred_replicas: HashSet::default(),
-            lamport_clock: clock::Lamport::new(LOCAL_BRANCH_REPLICA_ID),
+            lamport_clock: clock::Lamport::new(ReplicaId::LOCAL_BRANCH),
             subscriptions: Default::default(),
             edit_id_resolvers: Default::default(),
             wait_for_version_txs: Default::default(),
@@ -1254,7 +1251,7 @@ impl Buffer {
         for edit_id in edit_ids {
             let insertion_slice = InsertionSlice {
                 edit_id: *edit_id,
-                insertion_id: clock::Lamport::default(),
+                insertion_id: clock::Lamport::MIN,
                 range: 0..0,
             };
             let slices = self
@@ -1858,7 +1855,7 @@ impl Buffer {
         T: rand::Rng,
     {
         let mut edits = self.get_random_edits(rng, edit_count);
-        log::info!("mutating buffer {} with {:?}", self.replica_id, edits);
+        log::info!("mutating buffer {:?} with {:?}", self.replica_id, edits);
 
         let op = self.edit(edits.iter().cloned());
         if let Operation::Edit(edit) = &op {
@@ -1881,7 +1878,7 @@ impl Buffer {
             if let Some(entry) = self.history.undo_stack.choose(rng) {
                 let transaction = entry.transaction.clone();
                 log::info!(
-                    "undoing buffer {} transaction {:?}",
+                    "undoing buffer {:?} transaction {:?}",
                     self.replica_id,
                     transaction
                 );
@@ -2918,7 +2915,10 @@ impl InsertionFragment {
 
 impl sum_tree::ContextLessSummary for InsertionFragmentKey {
     fn zero() -> Self {
-        Default::default()
+        InsertionFragmentKey {
+            timestamp: Lamport::MIN,
+            split_offset: 0,
+        }
     }
 
     fn add_summary(&mut self, summary: &Self) {