Slice 3: activity feed and active project (SSE + MCP tools)

Add internal/activity (thread-safe active project + bounded event feed with subscriber fan-out). Service exposes active-project/activity methods and takes the feed. New MCP tools get_active_project/set_active_project/get_activity and HTTP endpoints GET/POST /api/active-project, /api/activity, and /events (SSE). New <activity-feed> component updates live via EventSource; <repo-list> sets the active project on selection. Verified end-to-end in the running app: user actions push live events and set the active project (actor=user), all readable by Claude over MCP.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

internal/service/service.go

@@ -7,8 +7,10 @@ package service
 
 import (
 	"context"
+	"fmt"
 	"path/filepath"
 
+	"gitmanager/internal/activity"
 	"gitmanager/internal/git"
 	"gitmanager/internal/repos"
 )
@@ -17,11 +19,13 @@ import (
 type Service struct {
 	git   *git.CLI
 	index *repos.Index
+	feed  *activity.Feed
 }
 
-// New builds a Service over the git boundary and the scanner's repo index.
-func New(g *git.CLI, index *repos.Index) *Service {
-	return &Service{git: g, index: index}
+// New builds a Service over the git boundary, the scanner's repo index, and the
+// activity feed.
+func New(g *git.CLI, index *repos.Index, feed *activity.Feed) *Service {
+	return &Service{git: g, index: index, feed: feed}
 }
 
 // ListRepos returns a snapshot of every discovered repository.
@@ -45,3 +49,40 @@ func (s *Service) RepoDetail(ctx context.Context, path string) (repos.Detail, bo
 	}
 	return repos.BuildDetail(ctx, s.git, base), true
 }
+
+// --- Activity & active project (§8.2) --------------------------------------
+
+// ActiveProject returns the current active project path ("" if none).
+func (s *Service) ActiveProject() string {
+	return s.feed.ActiveProject()
+}
+
+// SetActiveProject makes path the active project (or clears it when empty). It
+// rejects a path that is not an indexed repository — the active project must be
+// a real repo (§1.3). Returns the recorded event and whether it changed.
+func (s *Service) SetActiveProject(actor activity.Actor, path string) (activity.Event, bool, error) {
+	if path != "" {
+		path = filepath.Clean(path)
+		if _, ok := s.index.Get(path); !ok {
+			return activity.Event{}, false, fmt.Errorf("unknown repository %q", path)
+		}
+	}
+	ev, changed := s.feed.SetActiveProject(actor, path)
+	return ev, changed, nil
+}
+
+// RecordActivity appends an arbitrary event to the feed.
+func (s *Service) RecordActivity(actor activity.Actor, kind, repo, detail string) activity.Event {
+	return s.feed.Record(actor, kind, repo, detail)
+}
+
+// Activity returns up to limit recent events, oldest first.
+func (s *Service) Activity(limit int) []activity.Event {
+	return s.feed.Events(limit)
+}
+
+// SubscribeActivity returns a channel of future events plus an unsubscribe func
+// the caller must invoke when done.
+func (s *Service) SubscribeActivity() (<-chan activity.Event, func()) {
+	return s.feed.Subscribe()
+}