Fix terminal cwd, selection highlight, comment range preservation

- Terminal now spawns in project sync directory so Claude Code can
  read/write .tex files
- Selection highlight uses semi-transparent color to layer above
  active line highlight
- External edits use diff-match-patch for minimal changes instead of
  full doc replace, preserving comment highlight positions
- Set connection state on project open so status bar shows Connected
- Remove cursor:pointer from comment highlights

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

6 files changed, 37 insertions, 11 deletions

diff --git a/src/renderer/src/components/Editor.tsx b/src/renderer/src/components/Editor.tsx
index 649b238..4328c22 100644
--- a/src/renderer/src/components/Editor.tsx
+++ b/src/renderer/src/components/Editor.tsx
@@ -32,9 +32,10 @@ const cosmicLatteTheme = EditorView.theme({
     color: '#3B3228', padding: '8px 0'
   },
   '.cm-cursor': { borderLeftColor: '#3B3228' },
-  '.cm-activeLine': { backgroundColor: '#F5EDD6' },
-  '.cm-activeLineGutter': { backgroundColor: '#F5EDD6' },
-  '.cm-selectionBackground, ::selection': { backgroundColor: '#B8D4E3 !important' },
+  '.cm-activeLine': { backgroundColor: 'rgba(214, 206, 188, 0.3)' },
+  '.cm-activeLineGutter': { backgroundColor: 'rgba(214, 206, 188, 0.3)' },
+  '.cm-selectionBackground, ::selection': { backgroundColor: 'rgba(120, 170, 210, 0.45) !important' },
+  '&.cm-focused .cm-selectionBackground': { backgroundColor: 'rgba(120, 170, 210, 0.45) !important' },
   '.cm-gutters': {
     backgroundColor: '#F5EDD6', color: '#A09880', border: 'none',
     borderRight: '1px solid #D6CEBC', paddingRight: '8px'
diff --git a/src/renderer/src/components/ProjectList.tsx b/src/renderer/src/components/ProjectList.tsx
index d5b382c..a3c9c37 100644
--- a/src/renderer/src/components/ProjectList.tsx
+++ b/src/renderer/src/components/ProjectList.tsx
@@ -65,6 +65,8 @@ export default function ProjectList({ onOpenProject }: Props) {
       if (result.fileRefs) store.setFileRefs(result.fileRefs)
       if (result.rootFolderId) store.setRootFolderId(result.rootFolderId)
       store.setOverleafProjectId(pid)
+      store.setConnectionState('connected')
+      if (result.syncDir) store.setSyncDir(result.syncDir)
       setStatusMessage('Connected')
       onOpenProject(pid)
     } else {
diff --git a/src/renderer/src/components/Terminal.tsx b/src/renderer/src/components/Terminal.tsx
index 3781a53..e2eb5e8 100644
--- a/src/renderer/src/components/Terminal.tsx
+++ b/src/renderer/src/components/Terminal.tsx
@@ -55,8 +55,9 @@ export default function Terminal() {
     xtermRef.current = xterm
     fitAddonRef.current = fitAddon
 
-    // Spawn shell
-    window.api.ptySpawn('/tmp')
+    // Spawn shell in project sync directory
+    const syncDir = useAppStore.getState().syncDir || '/tmp'
+    window.api.ptySpawn(syncDir)
 
     // Pipe data
     const unsubData = window.api.onPtyData((data) => {
diff --git a/src/renderer/src/extensions/commentHighlights.ts b/src/renderer/src/extensions/commentHighlights.ts
index 3215026..8ea1cd7 100644
--- a/src/renderer/src/extensions/commentHighlights.ts
+++ b/src/renderer/src/extensions/commentHighlights.ts
@@ -220,7 +220,6 @@ const commentHighlightTheme = EditorView.baseTheme({
     backgroundColor: 'rgba(243, 177, 17, 0.25)',
     borderBottom: '2px solid rgba(243, 177, 17, 0.5)',
     padding: '1px 0',
-    cursor: 'pointer',
   },
   '.cm-comment-highlight-hover': {
     backgroundColor: 'rgba(243, 177, 17, 0.45)',
diff --git a/src/renderer/src/ot/overleafSync.ts b/src/renderer/src/ot/overleafSync.ts
index 787a458..1c6672b 100644
--- a/src/renderer/src/ot/overleafSync.ts
+++ b/src/renderer/src/ot/overleafSync.ts
@@ -3,7 +3,8 @@
 
 // Per-document orchestrator: ties CM6 adapter to OT client, IPC bridge
 import type { EditorView } from '@codemirror/view'
-import { ChangeSet, Transaction, type Text } from '@codemirror/state'
+import { ChangeSet, Transaction, type ChangeSpec, type Text } from '@codemirror/state'
+import { diff_match_patch } from 'diff-match-patch'
 import { OtClient } from './otClient'
 import type { OtOp } from './types'
 import { changeSetToOtOps, otOpsToChangeSpec } from './cmAdapter'
@@ -136,10 +137,27 @@ export class OverleafDocSync {
     const currentContent = this.view.state.doc.toString()
     if (currentContent === newContent) return
 
-    // Dispatch as a local change (NOT remote annotation) so it flows through OT
-    this.view.dispatch({
-      changes: { from: 0, to: this.view.state.doc.length, insert: newContent }
-    })
+    // Use diff to compute minimal changes so comment range positions remap correctly
+    const dmp = new diff_match_patch()
+    const diffs = dmp.diff_main(currentContent, newContent)
+    dmp.diff_cleanupEfficiency(diffs)
+
+    const changes: ChangeSpec[] = []
+    let pos = 0
+    for (const [type, text] of diffs) {
+      if (type === 0) { // EQUAL
+        pos += text.length
+      } else if (type === -1) { // DELETE
+        changes.push({ from: pos, to: pos + text.length })
+        pos += text.length
+      } else if (type === 1) { // INSERT
+        changes.push({ from: pos, to: pos, insert: text })
+      }
+    }
+
+    if (changes.length > 0) {
+      this.view.dispatch({ changes })
+    }
   }
 
   destroy() {
diff --git a/src/renderer/src/stores/appStore.ts b/src/renderer/src/stores/appStore.ts
index 9e1e141..adb4957 100644
--- a/src/renderer/src/stores/appStore.ts
+++ b/src/renderer/src/stores/appStore.ts
@@ -90,6 +90,8 @@ interface AppState {
   setFileRefs: (refs: Array<{ id: string; path: string }>) => void
   rootFolderId: string
   setRootFolderId: (id: string) => void
+  syncDir: string
+  setSyncDir: (dir: string) => void
 
   // Review panel
   showReviewPanel: boolean
@@ -198,6 +200,8 @@ export const useAppStore = create<AppState>((set) => ({
   setFileRefs: (refs) => set({ fileRefs: refs }),
   rootFolderId: '',
   setRootFolderId: (id) => set({ rootFolderId: id }),
+  syncDir: '',
+  setSyncDir: (dir) => set({ syncDir: dir }),
 
   showReviewPanel: false,
   toggleReviewPanel: () => set((s) => ({ showReviewPanel: !s.showReviewPanel })),
@@ -240,6 +244,7 @@ export const useAppStore = create<AppState>((set) => ({
     overleafProject: null,
     fileRefs: [],
     rootFolderId: '',
+    syncDir: '',
     commentContexts: {},
     overleafDocs: {},
     hoveredThreadId: null,