refactor: remove all deletions.jsonl code (bd-fom)

Complete removal of the legacy deletions.jsonl manifest system.
Tombstones are now the sole deletion mechanism.

Removed:
- internal/deletions/ - entire package
- cmd/bd/deleted.go - deleted command
- cmd/bd/doctor/fix/deletions.go - HydrateDeletionsManifest
- Tests for all removed functionality

Cleaned:
- cmd/bd/sync.go - removed sanitize, auto-compact
- cmd/bd/delete.go - removed dual-writes
- cmd/bd/doctor.go - removed checkDeletionsManifest
- internal/importer/importer.go - removed deletions checks
- internal/syncbranch/worktree.go - removed deletions merge
- cmd/bd/integrity.go - updated validation (warn-only on decrease)

Files removed: 12
Lines removed: ~7500

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

internal/syncbranch/worktree_divergence_test.go

@@ -313,96 +313,6 @@ func TestPerformContentMerge(t *testing.T) {
 	})
 }
 
-// TestPerformDeletionsMerge tests the deletions merge function
-func TestPerformDeletionsMerge(t *testing.T) {
-	if testing.Short() {
-		t.Skip("skipping integration test in short mode")
-	}
-
-	ctx := context.Background()
-
-	t.Run("merges deletions from both sides", func(t *testing.T) {
-		repoDir := setupTestRepo(t)
-		defer os.RemoveAll(repoDir)
-
-		runGit(t, repoDir, "checkout", "-b", "test-branch")
-
-		// Base: no deletions
-		writeFile(t, filepath.Join(repoDir, ".beads", "issues.jsonl"), `{"id":"test-1"}`)
-		runGit(t, repoDir, "add", ".")
-		runGit(t, repoDir, "commit", "-m", "base commit")
-		baseCommit := strings.TrimSpace(getGitOutput(t, repoDir, "rev-parse", "HEAD"))
-
-		// Local: delete issue-A
-		writeFile(t, filepath.Join(repoDir, ".beads", "deletions.jsonl"), `{"id":"issue-A","deleted_at":"2024-01-01T00:00:00Z"}`)
-		runGit(t, repoDir, "add", ".")
-		runGit(t, repoDir, "commit", "-m", "local deletion")
-		localHead := strings.TrimSpace(getGitOutput(t, repoDir, "rev-parse", "HEAD"))
-
-		// Remote: delete issue-B
-		runGit(t, repoDir, "checkout", baseCommit)
-		writeFile(t, filepath.Join(repoDir, ".beads", "deletions.jsonl"), `{"id":"issue-B","deleted_at":"2024-01-02T00:00:00Z"}`)
-		runGit(t, repoDir, "add", ".")
-		runGit(t, repoDir, "commit", "-m", "remote deletion")
-		runGit(t, repoDir, "update-ref", "refs/remotes/origin/test-branch", "HEAD")
-
-		// Go back to local
-		runGit(t, repoDir, "checkout", "-B", "test-branch", localHead)
-
-		// Perform merge
-		merged, err := performDeletionsMerge(ctx, repoDir, "test-branch", "origin", ".beads/deletions.jsonl")
-		if err != nil {
-			t.Fatalf("performDeletionsMerge() error = %v", err)
-		}
-
-		// Both deletions should be present
-		mergedStr := string(merged)
-		if !strings.Contains(mergedStr, "issue-A") {
-			t.Error("merged deletions missing issue-A")
-		}
-		if !strings.Contains(mergedStr, "issue-B") {
-			t.Error("merged deletions missing issue-B")
-		}
-	})
-
-	t.Run("handles only local deletions", func(t *testing.T) {
-		repoDir := setupTestRepo(t)
-		defer os.RemoveAll(repoDir)
-
-		runGit(t, repoDir, "checkout", "-b", "test-branch")
-
-		// Base: no deletions
-		writeFile(t, filepath.Join(repoDir, ".beads", "issues.jsonl"), `{"id":"test-1"}`)
-		runGit(t, repoDir, "add", ".")
-		runGit(t, repoDir, "commit", "-m", "base commit")
-		baseCommit := strings.TrimSpace(getGitOutput(t, repoDir, "rev-parse", "HEAD"))
-
-		// Local: has deletions
-		writeFile(t, filepath.Join(repoDir, ".beads", "deletions.jsonl"), `{"id":"issue-A"}`)
-		runGit(t, repoDir, "add", ".")
-		runGit(t, repoDir, "commit", "-m", "local deletion")
-		localHead := strings.TrimSpace(getGitOutput(t, repoDir, "rev-parse", "HEAD"))
-
-		// Remote: no deletions file
-		runGit(t, repoDir, "checkout", baseCommit)
-		runGit(t, repoDir, "update-ref", "refs/remotes/origin/test-branch", "HEAD")
-
-		// Go back to local
-		runGit(t, repoDir, "checkout", "-B", "test-branch", localHead)
-
-		// Perform merge
-		merged, err := performDeletionsMerge(ctx, repoDir, "test-branch", "origin", ".beads/deletions.jsonl")
-		if err != nil {
-			t.Fatalf("performDeletionsMerge() error = %v", err)
-		}
-
-		// Local deletions should be present
-		if !strings.Contains(string(merged), "issue-A") {
-			t.Error("merged deletions missing issue-A")
-		}
-	})
-}
-
 // Helper functions
 
 func setupTestRepo(t *testing.T) string {