Prepare for v25.12 release

[ahopkins]

No description provided.

[Copilot]

Pull request overview

This PR prepares Sanic for the v25.12 Long Term Support (LTS) release, updating version numbers, dependencies, changelog, and documentation.

• Updates version from 25.3.0 to 25.12.0 across all relevant files
• Refactors worker process logging for better clarity on startup sequence
• Updates documentation dependencies to support newer versions (mistune>=2.0.0, adds msgspec, python-frontmatter, docstring-parser, libsass)

Reviewed changes

Copilot reviewed 13 out of 13 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
sanic/__version__.py	Bumps version to 25.12.0
sanic/server/runners.py	Refactors PID handling to pass as parameter; updates worker log messages to distinguish "Starting" from "Worker ready"
sanic/app.py	Removes unused loop parameter from methods; uses asyncio.get_running_loop() internally
setup.py	Updates mistune constraint to >=2.0.0; adds documentation dependencies
guide/content/en/release-notes/changelog.md	Adds v25.12.0 changelog entries; moves previous version down
guide/content/en/release-notes/2025/v25.12.md	Adds comprehensive v25.12 LTS release notes with feature documentation
guide/content/en/guide/running/running.md	Documents new daemon mode feature
guide/content/en/guide/running/configuration.md	Documents DetailedConverter feature
guide/content/en/guide/basics/tasks.md	Documents that add_task returns Task object
guide/content/en/guide/basics/routing.md	Documents symlink control parameters for static files
guide/content/en/guide/advanced/commands.md	Removes outdated version notice
guide/config/en/sidebar.yaml	Adds v25.12 to release notes navigation
guide/config/en/general.yaml	Updates current_version to 25.12

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 87.817%. Comparing base (dc0939e) to head (d9738d8).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@              Coverage Diff              @@
##              main     #3124       +/-   ##
=============================================
+ Coverage   87.811%   87.817%   +0.005%     
=============================================
  Files          105       105               
  Lines         8139      8143        +4     
  Branches      1290      1290               
=============================================
+ Hits          7147      7151        +4     
  Misses         686       686               
  Partials       306       306               

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