feat(security): add dedicated install flags decoupled from security_level

Gate 'install via git URL' and 'install via pip' with dedicated opt-in
boolean flags (allow_git_url_install / allow_pip_install) in config.ini
[default], fully replacing the security_level term on those surfaces
(REPLACE, not AND — a strict level no longer denies when the flag is on;
a weak level no longer allows when the flag is off).

- glob/manager_server.py: pure predicate is_dedicated_install_allowed
  (flag AND loopback, request-time args.listen); REPLACE gates at
  /customnode/install/git_url and /customnode/install/pip; batch
  unknown-URL arm routes through the same full predicate at the risky
  position (loopback term is load-bearing — the middle entry gate has
  no network-position term; the entry gate itself stays in force);
  unknown-pip in batch stays unconditionally blocked; new
  SECURITY_MESSAGE_FLAG_* denial constants name the responsible flag;
  security_403_response gains flag_token (comfyui_outdated keeps precedence)
- glob/manager_core.py: register both keys (read via get_bool default-false,
  write list, exception fallback); "true"-only truthy; restart-only activation
- js/common.js: 403 dialog copy names the responsible flag at the two
  install call sites
- README.md: security-policy docs for both flags (per-surface scope incl.
  the batch entry-gate qualifier, REPLACE decoupling, loopback bound,
  opt-in config snippet, default-deny + migration note); stale tier lists
  corrected against the actual gates
- CHANGELOG.md: opt-in migration note + accepted residual risk (flags
  bypass the forced-strong outdated-ComfyUI hardening on loopback,
  opt-in only), decoupling claim qualified for the batch entry gate

Tests: unit suite (predicate truth table, REPLACE litmus both directions,
AST binding-proofs against live handlers, subprocess-isolated config
contract) plus a real-server E2E suite that mounts the Manager-under-test
via git worktree (exact-SHA pin, detached) against a real ComfyUI and
exercises both flag surfaces and both arms — deny arms (403 + flag-naming
body/log + no install artifact), git-URL allow arm (real clone), pip allow
arm as a two-phase reservation oracle — with zero-residual self-clean.
Module skips without E2E_COMFYUI_ROOT; unit suite unaffected.

The manager-v4 branch ships the identical policy (shared invariants +
config contract); this tree uses the degraded predicate 'flag AND
loopback' (no personal_cloud-equivalent mode here).

node_db/legacy/custom-node-list.json

@@ -1,55 +1,5 @@
 {
     "custom_nodes": [
-        {
-            "author": "ComfyuiGY",
-            "title": "Comfyui-Memory-Clear [REMOVED]",
-            "reference": "https://github.com/ComfyuiGY/Comfyui-Memory-Clear",
-            "files": [
-                "https://github.com/ComfyuiGY/Comfyui-Memory-Clear"
-            ],
-            "install_type": "git-clone",
-            "description": "ComfyUI node for clearing memory. (Description by CC)"
-        },
-        {
-            "author": "Draek2077",
-            "title": "comfyui-draekz-nodez [REMOVED]",
-            "reference": "https://github.com/Draek2077/comfyui-draekz-nodez",
-            "files": [
-                "https://github.com/Draek2077/comfyui-draekz-nodez"
-            ],
-            "install_type": "git-clone",
-            "description": "Making ComfyUI more comfortable."
-        },
-        {
-            "author": "amortegui84",
-            "title": "Tile Upscale NB2 [REMOVED]",
-            "reference": "https://github.com/amortegui84/comfyui-tile-upscale-nb2",
-            "files": [
-                "https://github.com/amortegui84/comfyui-tile-upscale-nb2"
-            ],
-            "install_type": "git-clone",
-            "description": "Tile-based upscaling nodes for ComfyUI — Nano Banana 2 compatible"
-        },
-        {
-            "author": "Aero-Ex",
-            "title": "ComfyUI Vision LLM Analyzer Node [REMOVED]",
-            "reference": "https://github.com/Aero-Ex/ComfyUI-Vision-LLM-Analyzer",
-            "files": [
-                "https://github.com/Aero-Ex/ComfyUI-Vision-LLM-Analyzer"
-            ],
-            "install_type": "git-clone",
-            "description": "This repository contains a powerful and versatile custom node for ComfyUI that seamlessly integrates with OpenAI-compatible Large Language Models (LLMs), including multimodal (vision-enabled) models like GPT-4o.\nThis single node allows you to perform both text generation and image analysis, making it an essential tool for advanced prompt engineering and creative automation."
-        },
-        {
-            "author": "Aero-Ex",
-            "title": "comfyui_diffswap [REMOVED]",
-            "reference": "https://github.com/Aero-Ex/comfyui_diffswap",
-            "files": [
-                "https://github.com/Aero-Ex/comfyui_diffswap"
-            ],
-            "install_type": "git-clone",
-            "description": "NODES: DiffSwap"
-        },
         {
             "author": "Sakura-nee",
             "title": "ComfyUI_Save2Discord [REMOVED]",