docs(fix[gallery]): resolve 9 directive errors and 3 duplicate-module warnings

why: Someone sprinkled `:noindex:` across `docs/gallery.md` hoping
to silence `duplicate object description of gp_demo_api |
spf_demo_fixtures | api_demo_layout` warnings, but the duplicates
actually originate in three `{py:module}` MyST blocks — while the
`:noindex:` option was being applied to seven custom `SphinxDirective`
subclasses that either do not register any domain object (six of
them) or only accept the modern dashed form `:no-index:` (one of
them, `autoconfigvalues`, which already declares it in `option_spec`).
The result: 9 "maximum 1 argument supplied" / "unknown option" /
"no content permitted" errors per build, plus the original 3 dup
warnings untouched. Sphinx 5+ canonicalized the dashed spelling;
only `ObjectDescription` subclasses honour the legacy alias
(`sphinx/directives/__init__.py:226–237`).
what:
- Add `:no-index:` to the three `{py:module}` MyST blocks
  (gp_demo_api, api_demo_layout, spf_demo_fixtures) — these are
  the real source of the duplicate warnings; the per-package
  detail pages remain the canonical registration
- Drop meaningless `:noindex:` from six pure-render directives
  (`fastmcp-tool` ×3, `fastmcp-tool-input`, `fastmcp-tool-summary`,
  `autoconfigvalue-index`, `autodirective-index`, `autorole-index`)
  — each emits only sections/tables with no domain registration, so
  the flag was a no-op that currently errors out
- Fix the one spelling mistake: `autoconfigvalues :noindex:`
  → `:no-index:` (the directive already declares
  `option_spec = {"no-index": directives.flag}` and registers
  `py:data` objects, so the dashed form is what it expects)
- No source changes to any custom directive: six of the seven
  register no domain objects, so adding an empty `option_spec`
  solely to swallow `:no-index:` would silently mask user mistakes
  instead of surfacing them
- Build now `build succeeded.` with zero warnings (was
  `build succeeded, 12 warnings`)

Author: tony

docs/gallery.md

@@ -14,6 +14,7 @@ Badges, type hints, and card layout working together on standard Python domain
 directives.
 
 ```{py:module} gp_demo_api
+:no-index:
 ```
 
 ### Functions
@@ -73,6 +74,7 @@ Large parameter lists fold automatically.  The class below has 13 parameters
 disclosure widget.
 
 ```{py:module} api_demo_layout
+:no-index:
 ```
 
 ### Class with members (regions + fold)
@@ -108,34 +110,30 @@ Tool documentation with safety badges and parameter tables.
 
 ```{eval-rst}
 .. fastmcp-tool:: fastmcp_demo_tools.list_sessions
-   :noindex:
 
 .. fastmcp-tool:: fastmcp_demo_tools.create_session
-   :noindex:
 
 .. fastmcp-tool:: fastmcp_demo_tools.delete_session
-   :noindex:
 ```
 
 ### Parameter table
 
 ```{eval-rst}
 .. fastmcp-tool-input:: fastmcp_demo_tools.create_session
-   :noindex:
 ```
 
 ### Tool summary
 
 ```{eval-rst}
 .. fastmcp-tool-summary::
-   :noindex:
 ```
 
 ---
 
 ## pytest fixtures
 
 ```{py:module} spf_demo_fixtures
+:no-index:
 ```
 
 ### Fixture index
@@ -156,12 +154,11 @@ Tool documentation with safety badges and parameter tables.
 
 ```{eval-rst}
 .. autoconfigvalue-index:: sphinx_config_demo
-   :noindex:
 ```
 
 ```{eval-rst}
 .. autoconfigvalues:: sphinx_config_demo
-   :noindex:
+   :no-index:
 ```
 
 ---
@@ -172,7 +169,6 @@ Tool documentation with safety badges and parameter tables.
 
 ```{eval-rst}
 .. autodirective-index:: docutils_demo
-   :noindex:
 ```
 
 ```{eval-rst}
@@ -184,7 +180,6 @@ Tool documentation with safety badges and parameter tables.
 
 ```{eval-rst}
 .. autorole-index:: docutils_demo
-   :noindex:
 ```
 
 ```{eval-rst}