Initial commit: hardened DeerFlow factory

Vendored deer-flow upstream (bytedance/deer-flow) plus prompt-injection
hardening:

- New deerflow.security package: content_delimiter, html_cleaner,
  sanitizer (8 layers — invisible chars, control chars, symbols, NFC,
  PUA, tag chars, horizontal whitespace collapse with newline/tab
  preservation, length cap)
- New deerflow.community.searx package: web_search, web_fetch,
  image_search backed by a private SearX instance, every external
  string sanitized and wrapped in <<<EXTERNAL_UNTRUSTED_CONTENT>>>
  delimiters
- All native community web providers (ddg_search, tavily, exa,
  firecrawl, jina_ai, infoquest, image_search) replaced with hard-fail
  stubs that raise NativeWebToolDisabledError at import time, so a
  misconfigured tool.use path fails loud rather than silently falling
  back to unsanitized output
- Native client back-doors (jina_client.py, infoquest_client.py)
  stubbed too
- Native-tool tests quarantined under tests/_disabled_native/
  (collect_ignore_glob via local conftest.py)
- Sanitizer Layer 7 fix: only collapse horizontal whitespace, preserve
  newlines and tabs so list/table structure survives
- Hardened runtime config.yaml references only the searx-backed tools
- Factory overlay (backend/) kept in sync with deer-flow tree as a
  reference / source

See HARDENING.md for the full audit trail and verification steps.

deer-flow/skills/public/image-generation/templates/doraemon.md

@@ -0,0 +1,112 @@
+# Doraemon 8-Panel Comic Generator
+
+## Workflow
+
+1. Extract story context (theme, gadget, conflict, punchline)
+2. Map to 8 narrative beats
+3. Use the provided prompt template to generate the JSON prompt file
+
+## Panel Layout
+
+```
+┌─────────┬─────────┐
+│ Panel 1 │ Panel 2 │  Row 1: y=200, height=380
+├─────────┼─────────┤
+│ Panel 3 │ Panel 4 │  Row 2: y=600, height=380
+├─────────┼─────────┤
+│ Panel 5 │ Panel 6 │  Row 3: y=1000, height=380
+├─────────┼─────────┤
+│ Panel 7 │ Panel 8 │  Row 4: y=1400, height=380
+└─────────┴─────────┘
+Left column: x=90, width=450
+Right column: x=540, width=450
+```
+
+## Characters
+
+* Doraemon
+* Nobita
+* Shizuka
+* Giant
+* Suneo
+
+## Prompt Template
+
+```json
+{
+  "canvas": {
+    "width": 1080,
+    "height": 1920,
+    "background": { "type": "solid", "color": "#F0F8FF" }
+  },
+  "header": {
+    "title": {
+      "text": "[Story Title]",
+      "position": { "x": 540, "y": 100 },
+      "style": {
+        "font_family": "Doraemon, sans-serif",
+        "font_size": 56,
+        "font_weight": "bold",
+        "color": "#0095D9",
+        "text_align": "center",
+        "stroke": "#FFFFFF",
+        "stroke_width": 4,
+        "text_shadow": "3px 3px 0px #FFD700"
+      }
+    }
+  },
+  "panels": [
+    {
+      "id": "panel1",
+      "position": { "x": 90, "y": 200 },
+      "size": { "width": 450, "height": 380 },
+      "border": { "width": 4, "color": "#000000", "radius": 12 },
+      "background": "#FFFFFF",
+      "scene": {
+        "location": "[Location name]",
+        "characters": [
+          {
+            "name": "[Character]",
+            "position": { "x": 0, "y": 0 },
+            "expression": "[Expression]",
+            "pose": "[Pose description]"
+          }
+        ],
+        "dialogues": [
+          {
+            "speaker": "[Character]",
+            "text": "[Dialogue text]",
+            "position": { "x": 0, "y": 0 },
+            "style": {
+              "bubble_type": "speech",
+              "backgroundColor": "#FFFFFF",
+              "border_color": "#000000",
+              "font_size": 22,
+              "text_align": "center"
+            }
+          }
+        ],
+        "props": []
+      }
+    }
+  ],
+  "footer": {
+    "text": "[Closing note] - Doraemon",
+    "position": { "x": 540, "y": 1860 },
+    "style": {
+      "font_family": "Doraemon, sans-serif",
+      "font_size": 24,
+      "color": "#0095D9",
+      "text_align": "center"
+    }
+  },
+}
+```
+
+## Story Pattern
+
+Setup → Problem → Gadget → Misuse → Backfire → Chaos → Consequence → Ironic Punchline
+
+## Aspect Ratio
+
+9:16