[18.0] [MIG] ai_automation -> ai_server_action

[angelmoya]

[MIG] ai_automation -> ai_server_action: migration to 18.0

• Renamed module from ai_automation to ai_server_action
• Removed ai_connection model (now in base ai_connection module)
• Added output modes: post_message, update_record, store_variable, none
• Added markdown rendering support for HTML fields
• Added template variable support via Qweb
• Rewrote tests using FakeModelLoader pattern (no real API calls)

Depends on #77

[angelmoya]

Additionally, regarding the commit order, it might be better to split it. We could first do the migration and adaptation work to version 18 relying on the connection, and then handle the name change in a separate, subsequent commit.

This way, the actual changes between versions would be much easier to track and review.

[angelmoya]

@etobella @pedrobaeza I have updated the PR and split the work into three clean commits: migration, refactoring, and module renaming.

If we decide not to rename the module, I can easily revert to the previous commit. Ready for review.

[etobella]

@angelmoya Rename is not handled this way. I requires to modify previous commits because, otherwise, on the next migration everything will be lost...

[etobella]

Please, remake history and just leave a migration commit.

The code is something like:

git filter-branch -f --index-filter '
git ls-files --stage | \
sed "s:ai_automation/:ai_server_action/:" | \
GIT_INDEX_FILE=$GIT_INDEX_FILE.new \
git update-index --index-info && \
mv "$GIT_INDEX_FILE.new" "$GIT_INDEX_FILE"
' HEAD

Also, there is some comments to be attended