docs: add file.patch and Gmail Pub/Sub watcher documentation

- README: features list, Gmail config section with field reference and
  template variables, hook examples, architecture tree, CLI description
- CHANGELOG: new Added entries for both features
- SOUL.md: file.patch in capabilities list
- config/default.yaml: file.patch in confirm hooks, commented-out
  automation section with cron, webhooks, gmail, heartbeat examples

config/default.yaml

@@ -66,8 +66,50 @@ hooks:
   confirm:
     - shell.*
     - file.write
+    - file.patch
   log:
     - web.*
     - file.read
   silent:
     - notify
+
+# ── Automation ──────────────────────────────────────────────────────
+# Uncomment and configure any automation sources you need.
+
+# automation:
+#   cron:
+#     - name: daily-summary
+#       schedule: "0 9 * * *"
+#       message: "Give me a summary of today's tasks"
+#       output:
+#         channel: telegram
+#         peer: "123456789"
+#
+#   webhooks:
+#     - name: github-push
+#       secret: "whsec_..."
+#       message: "GitHub push to {{json.repository.full_name}}: {{json.head_commit.message}}"
+#       output:
+#         channel: telegram
+#         peer: "123456789"
+#
+#   gmail:
+#     enabled: false
+#     credentials_file: ~/.config/flynn/gmail-credentials.json
+#     token_file: ~/.config/flynn/gmail-token.json
+#     watch_labels: [INBOX]
+#     poll_interval: "60s"
+#     message: "New email from {{from}}: {{subject}}\n\n{{snippet}}"
+#     output:
+#       channel: telegram
+#       peer: "123456789"
+#
+#   heartbeat:
+#     enabled: false
+#     interval: "5m"
+#     checks: [gateway, model, channels, memory, disk]
+#     notify:
+#       channel: telegram
+#       peer: "123456789"
+#     failure_threshold: 2
+#     disk_threshold_mb: 100