Add Custom Field Tag Filter plugin

[DexXxter103]

Custom Field Tag Filter

Adds a new UI plugin that hides "meta-tags" from manual tag entry (when editing
scenes) and, optionally, from scraper results. Which tags are hidden is controlled
by a custom field on the tag — so the marking lives in the stash database
itself.

Why

This is a self-contained alternative to the existing tag-filter plugin. That
plugin stores the hidden-tag list in the browser's localStorage, so the list
is lost when you clear your browser cache or use a different browser, forcing you
to re-mark every tag. Storing the marking on the tag (via a custom field) means
it's shared across browsers and survives cache clears.

What it does

• Hides marked tags from the scene tag dropdown (FindTagsForSelect)
• Hides marked tags from the scraper's automatic tag search
• Optionally strips marked tags from scrape results (setting)

It does not hide tags from the /tags page, scenes that already have the tag,
or the backend.

How it works

• Fully self-contained: no dependency on helper plugins (0gql-intercept,
  forbiddenConfig, wfke, fontawesome-js). It inlines a minimal fetch
  interceptor and reads its own settings via GraphQL.
• The hidden-tag list is fetched lazily, once per page load — the first time a
  tag dropdown or scrape result is shown — then reused for the session. No
  background polling, so simply browsing generates no extra traffic. This mirrors
  Stash's own cache-first behavior (changes made elsewhere are picked up on reload).

Settings

Setting	Description
Custom field name	The custom field that marks a tag as hidden. Required.
Custom field value (optional)	If set, only tags whose field equals this value are hidden; empty = any non-empty value.
Also hide marked tags from scraper results	Strip marked tags from scrape results.

Testing

• Tag-selection filtering on the scene edit page works (presence-only matching);
  marked tags remain visible on /tags.
• With the scrape setting off, scraping a scene issues no GraphQL calls from
  the plugin (no extra traffic while browsing/scraping).
• With the scrape setting on, a tag returned by the scraper that is marked as
  filtered is correctly stripped from the scrape results.
• With an optional custom field value set (strict matching), tags whose field
  has a non-matching value are not filtered, while tags with the matching value
  are filtered.
• Validated with the repo validator (node validate.js).

Disclosure

Written with LLM assistance per the repository's LLM-assisted contribution policy;
reviewed and tested by me, and I take full responsibility for the code.

Link: stashapp/stash#2633 (comment)