Improve tools reliability and add milestone management to ProjectView

tools.py:
- Default tag_mode changed from 'replace' to 'add' — existing tags are
  preserved unless the user explicitly requests replacement
- create_task, create_note, update_note, create_milestone: project and
  milestone lookup now uses get_by_title with fuzzy fallback; returns a
  clear error (with a hint to use list_projects/list_milestones) instead
  of silently creating duplicate projects or milestones via get_or_create
- create_task: project/milestone resolved before note creation so a bad
  project name fails fast without leaving an orphaned task behind
- update_note return value now includes item_type, tags, project_id, and
  an 'updated' summary string so the LLM can confirm what was modified
- research_topic stub now logs an error and returns failure instead of
  silently returning success when reached via wrong code path

ProjectView.vue:
- Milestone headers now show edit (✎) and delete (✕) action buttons on hover
- Edit triggers inline rename input; Enter/blur commits, Escape cancels
- Delete opens a confirmation modal clarifying tasks are unlinked not deleted

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

frontend/src/views/ProjectView.vue

@@ -65,6 +65,11 @@ const showNewMilestone = ref(false);
 const newMilestoneTitle = ref("");
 const creatingMilestone = ref(false);
 
+// Milestone edit/delete state
+const renamingMilestoneId = ref<number | null>(null);
+const renamingMilestoneTitle = ref("");
+const deletingMilestone = ref<Milestone | null>(null);
+
 // Edit state
 const editTitle = ref("");
 const editDescription = ref("");
@@ -156,6 +161,38 @@ async function createMilestone() {
   }
 }
 
+function startRenameMilestone(ms: Milestone) {
+  renamingMilestoneId.value = ms.id;
+  renamingMilestoneTitle.value = ms.title;
+}
+
+async function commitRenameMilestone(ms: Milestone) {
+  const newTitle = renamingMilestoneTitle.value.trim();
+  renamingMilestoneId.value = null;
+  if (!newTitle || newTitle === ms.title) return;
+  try {
+    await apiPatch(`/api/projects/${projectId.value}/milestones/${ms.id}`, { title: newTitle });
+    await loadMilestones();
+    toast.show("Milestone renamed");
+  } catch {
+    toast.show("Failed to rename milestone", "error");
+  }
+}
+
+async function confirmDeleteMilestone() {
+  const ms = deletingMilestone.value;
+  if (!ms) return;
+  deletingMilestone.value = null;
+  try {
+    await apiDelete(`/api/projects/${projectId.value}/milestones/${ms.id}`);
+    await loadMilestones();
+    await loadTasks();
+    toast.show("Milestone deleted");
+  } catch {
+    toast.show("Failed to delete milestone", "error");
+  }
+}
+
 async function loadTasks() {
   tasksLoading.value = true;
   try {
@@ -384,13 +421,25 @@ function formatDate(dateStr?: string | null): string {
                 <!-- Milestone header -->
                 <div
                   class="milestone-header"
-                  @click="group.milestone && toggleMilestoneCollapse(group.milestone.id)"
-                  :class="{ clickable: !!group.milestone }"
+                  @click="group.milestone && renamingMilestoneId !== group.milestone.id && toggleMilestoneCollapse(group.milestone.id)"
+                  :class="{ clickable: !!group.milestone && renamingMilestoneId !== group.milestone?.id }"
                 >
                   <span class="ms-chevron" v-if="group.milestone">
                     {{ collapsedMilestones.has(group.milestone.id) ? '▶' : '▼' }}
                   </span>
-                  <span class="ms-name">{{ group.milestone?.title ?? "No Milestone" }}</span>
+                  <!-- Inline rename input -->
+                  <template v-if="group.milestone && renamingMilestoneId === group.milestone.id">
+                    <input
+                      class="ms-rename-input"
+                      v-model="renamingMilestoneTitle"
+                      @click.stop
+                      @keydown.enter.stop="commitRenameMilestone(group.milestone)"
+                      @keydown.escape.stop="renamingMilestoneId = null"
+                      @blur="commitRenameMilestone(group.milestone)"
+                      autofocus
+                    />
+                  </template>
+                  <span v-else class="ms-name">{{ group.milestone?.title ?? "No Milestone" }}</span>
                   <span class="ms-count">{{ group.tasks.length }}</span>
                   <template v-if="group.milestone">
                     <div class="ms-progress-track">
@@ -400,6 +449,19 @@ function formatDate(dateStr?: string | null): string {
                       ></div>
                     </div>
                     <span class="ms-pct">{{ group.milestone.pct }}%</span>
+                    <!-- Edit / delete actions -->
+                    <div class="ms-actions" @click.stop>
+                      <button
+                        class="ms-action-btn"
+                        title="Rename milestone"
+                        @click="startRenameMilestone(group.milestone)"
+                      >✎</button>
+                      <button
+                        class="ms-action-btn ms-action-delete"
+                        title="Delete milestone"
+                        @click="deletingMilestone = group.milestone"
+                      >✕</button>
+                    </div>
                   </template>
                 </div>
 
@@ -497,7 +559,24 @@ function formatDate(dateStr?: string | null): string {
       </div>
     </template>
 
-    <!-- Delete confirmation modal -->
+    <!-- Milestone delete confirmation modal -->
+    <teleport to="body">
+      <div v-if="deletingMilestone" class="modal-overlay" @click.self="deletingMilestone = null">
+        <div class="modal-card">
+          <h3 class="modal-title">Delete Milestone</h3>
+          <p class="modal-message">
+            Delete <strong>{{ deletingMilestone.title }}</strong>?
+            Tasks will be unlinked from this milestone but not deleted.
+          </p>
+          <div class="modal-actions">
+            <button class="modal-btn" @click="deletingMilestone = null">Cancel</button>
+            <button class="modal-btn modal-btn-danger" @click="confirmDeleteMilestone">Delete</button>
+          </div>
+        </div>
+      </div>
+    </teleport>
+
+    <!-- Project delete confirmation modal -->
     <teleport to="body">
       <div v-if="showDeleteConfirm" class="modal-overlay" @click.self="showDeleteConfirm = false">
         <div class="modal-card">
@@ -1044,6 +1123,53 @@ function formatDate(dateStr?: string | null): string {
 }
 .modal-btn-danger:hover { opacity: 0.9; }
 
+/* Milestone rename input */
+.ms-rename-input {
+  flex: 1;
+  min-width: 0;
+  padding: 0.1rem 0.35rem;
+  border: 1px solid var(--color-primary);
+  border-radius: var(--radius-sm);
+  background: var(--color-bg);
+  color: var(--color-text);
+  font-size: 0.85rem;
+  font-family: inherit;
+  font-weight: 600;
+}
+.ms-rename-input:focus {
+  outline: none;
+}
+
+/* Milestone action buttons */
+.ms-actions {
+  display: flex;
+  gap: 0.15rem;
+  margin-left: 0.25rem;
+  opacity: 0;
+  transition: opacity 0.15s;
+}
+.milestone-header:hover .ms-actions {
+  opacity: 1;
+}
+.ms-action-btn {
+  background: none;
+  border: none;
+  cursor: pointer;
+  color: var(--color-text-muted);
+  font-size: 0.8rem;
+  padding: 0.15rem 0.3rem;
+  border-radius: var(--radius-sm);
+  line-height: 1;
+  font-family: inherit;
+}
+.ms-action-btn:hover {
+  background: var(--color-bg-card);
+  color: var(--color-text);
+}
+.ms-action-delete:hover {
+  color: var(--color-danger, #e74c3c);
+}
+
 @media (max-width: 900px) {
   .project-body {
     grid-template-columns: 1fr;