Fix broken submodule and add import memory optimization plan

- Remove broken submodule reference for pkg/protocol/blossom/blossom
  and track blossom spec files as regular files instead
- Add IMPORT_MEMORY_OPTIMIZATION_PLAN.md documenting strategies to
  constrain import memory usage to ≤1.5GB through cache reduction,
  batched syncs, batch transactions, and adaptive rate limiting
- Based on test results: 2.1M events imported in 48min at 736 events/sec
  with peak memory of 6.4GB (target is 1.5GB)

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

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

.claude/settings.local.json

@@ -57,7 +57,32 @@
       "Bash(go clean:*)",
       "Bash(go mod tidy:*)",
       "Bash(./scripts/test-neo4j-integration.sh:*)",
-      "Bash(docker compose:*)"
+      "Bash(docker compose:*)",
+      "Bash(sudo update-grub:*)",
+      "Bash(lspci:*)",
+      "Bash(lsmod:*)",
+      "Bash(modinfo:*)",
+      "Bash(apt-cache policy:*)",
+      "WebFetch(domain:git.kernel.org)",
+      "Bash(ip link:*)",
+      "WebFetch(domain:www.laptopcentar.rs)",
+      "WebFetch(domain:www.kupujemprodajem.com)",
+      "WebFetch(domain:www.bcgroup-online.com)",
+      "WebFetch(domain:www.monitor.rs)",
+      "WebFetch(domain:www.protis.hr)",
+      "Bash(apt-cache search:*)",
+      "Bash(dkms status:*)",
+      "Bash(sudo dkms build:*)",
+      "Bash(sudo apt install:*)",
+      "Bash(wget:*)",
+      "Bash(ls:*)",
+      "Bash(git clone:*)",
+      "Bash(sudo make:*)",
+      "Bash(sudo modprobe:*)",
+      "Bash(update-desktop-database:*)",
+      "Bash(CGO_ENABLED=0 go build:*)",
+      "Bash(CGO_ENABLED=0 go test:*)",
+      "Bash(git submodule:*)"
     ],
     "deny": [],
     "ask": []