Add pre_meeting_memo_html

[yujonglee]

https://github.com/fastrepl/hyprnote/blob/main/crates/db-user/src/sessions_migration_3.sql
just like this, add sessions_migration_4.sql

Should be added here:

hyprnote/crates/db-user/src/lib.rs

Lines 132 to 150 in 21d04ad

	const MIGRATIONS: [&str; 17] = [
	include_str!("./calendars_migration.sql"),
	include_str!("./configs_migration.sql"),
	include_str!("./events_migration.sql"),
	include_str!("./humans_migration.sql"),
	include_str!("./organizations_migration.sql"),
	include_str!("./sessions_migration.sql"),
	include_str!("./session_participants_migration.sql"),
	include_str!("./templates_migration.sql"),
	include_str!("./chat_groups_migration.sql"),
	include_str!("./chat_messages_migration.sql"),
	include_str!("./extension_mappings_migration.sql"),
	include_str!("./tags_migration.sql"),
	include_str!("./tag_sessions_migration.sql"),
	include_str!("./calendars_migration_1.sql"),
	include_str!("./sessions_migration_1.sql"),
	include_str!("./sessions_migration_2.sql"),
	include_str!("./sessions_migration_3.sql"),
	];

This should be updated too.
https://github.com/fastrepl/hyprnote/blob/main/crates/db-user/src/sessions_ops.rs

And generate bindings, etc

Can be default to empty - do whatever makes sense.

The idea is to seperate raw_note that is written before the meeting and after the meeting.
Current raw_memo_html stays same, just pre_meeting_memo_html is added.

When running enhance process, we want to only send raw_memo_html - pre_meeting_memo_html to LLM prompt. only memo during the meeting is important. But HTML is not diffable…

Tiptap3 support md IO.Tiptap2 do not support md, so we store it as html… Not sure what is good sol.

Need some updates on the frontend too, saving etc.

We might need to split this ticket into multiples.

at least @plyght can help with the sql update binding gen etc

[yujonglee]

Partially done #946
@duckduckhero will continue

[yujonglee]

#991