add a rule file encouraging proactive use of hot reload

[jakemac53]

Part of dart-lang/ai#498

It is not clear to me exactly which all agents support rules, but AGY does, and this rule has only been tested in AGY. Cursor supports it but seems to want a slightly different format, (.mdc).

Should we create separate directories for some of the other agents? I think cursor does support pointing to any directory for the rules in its plugin configuration.

[gemini-code-assist]

Code Review

This pull request introduces a new markdown rule file, rules/hot_reload.md, which outlines instructions for proactively connecting to Dart or Flutter applications and triggering hot reloads. A review comment correctly identifies a grammatical typo on line 8, where the contraction 'it's' should be replaced with the possessive pronoun 'its'.

[keertip]

As you have mentioned, cursor looks in the rules/ folder, but needs the file to be .mdc format. Claude code does not support rules, there's a open issue asking for rules support. Codex also does not directly support rules - rules in Codex are specified as system Instructions bundled inside a skill.

You can add a .mdc file in the rules/ folder for Cursor. AGY and Cursor will ignore the files not meant for them.

[jakemac53]

Ok, I added a cursor rule file which has a slightly different format as well.