feat(feed-plaintext): new generic plain-text threat-intel feed connector

Fetches a line-per-indicator blocklist URL and emits normalized IOCs {value,type}
for TIM import. Comment-char/field-index/type config, auto type-detection.
Optional bearer auth, stdlib-only. py_compile clean.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

integrations/feed-plaintext/manifest.yaml

@@ -0,0 +1,46 @@
+id: feed_plaintext
+name: Plain Text Feed
+version: 1.0.0
+description: "Generic plain-text threat-intel feed connector — fetch a line-per-indicator list from a URL (e.g. an IP or domain blocklist) and emit normalized IOCs (value + type) for import into the Threat Indicator Manager. One connector, many feeds. No authentication (or an optional bearer token); stdlib-only, no extra Python dependencies."
+changelog: "1.0.0 — Initial release: fetch indicators from a plain-text feed URL."
+category: feed
+
+# Per-instance configuration. The feed is fetched over HTTP(S) from feed_url.
+config_schema:
+  properties:
+    feed_url:
+      type: string
+      description: "URL of the plain-text feed (one indicator per line)"
+    api_token:
+      type: string
+      description: "Optional bearer token (if the feed requires auth)"
+      x-soar-sensitive: true
+    insecure:
+      type: boolean
+      description: "Trust any TLS certificate (not secure)"
+      default: false
+  required:
+    - feed_url
+
+commands:
+  - id: fetch_indicators
+    name: feed-plaintext-fetch-indicators
+    description: "Fetch and parse the plain-text feed, returning normalized indicators."
+    risk: read
+    inputs_schema:
+      properties:
+        ioc_type: { type: string, description: "auto | ip | domain | url | hash | email (default auto — detect per value)" }
+        comment_char: { type: string, description: "Lines starting with this are ignored (default '#')" }
+        field_index: { type: number, description: "If lines have multiple whitespace-separated fields, the 0-based field to take (default 0)" }
+        max_indicators: { type: number, description: "Max indicators to return (default 10000)" }
+      required: []
+    outputs_schema: { properties: {} }
+
+  - id: test_connection
+    name: feed-plaintext-test-connection
+    description: "Verify the feed URL is reachable (used by the Test button)."
+    risk: read
+    inputs_schema:
+      properties: {}
+      required: []
+    outputs_schema: { properties: {} }