Gitignore SESSION_HANDOFF.md, broaden CI trigger paths

SESSION_HANDOFF.md is local dev context, shouldn't be in repo.
Workflow now also triggers on docker-compose.yml and workflow
file changes (previously only watched src/, Dockerfile,
requirements.txt — which is why the initial commit never
triggered a build).

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

Author: stonks-git

.github/workflows/build.yml

@@ -7,6 +7,8 @@ on:
       - 'src/**'
       - 'requirements.txt'
       - 'Dockerfile'
+      - 'docker-compose.yml'
+      - '.github/workflows/**'
 
 env:
   REGISTRY: ghcr.io

.gitignore

@@ -27,6 +27,9 @@ Thumbs.db
 # Claude Code
 .claude/
 
+# Session handoff (local dev context, not deployed)
+SESSION_HANDOFF.md
+
 # Logs (agent generates these at runtime, not tracked)
 agent-state/logs/