Make the interests table the only source of standing interests (step 3)

The OPML file and the profile's ## Interests section become one-time
import inputs; the prompt groups by the stored category and the OPML
config key is gone.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01K9PrjtUS16PAQve8D4bHgc

src/main.rs

@@ -724,7 +724,6 @@ async fn cmd_profile_rebuild(config: &Config, db: &Db) -> Result<String> {
     use curate::llm::{Llms, provider_meters};
     let profile = curate::profile::load_or_build(
         db,
-        &config.interests_opml,
         &config.profile_path,
         config.curation.feedback.verdicts_in_prompt,
     )
@@ -749,7 +748,6 @@ async fn cmd_profile_rebuild(config: &Config, db: &Db) -> Result<String> {
     let rebuilt = curate::profile::rebuild(
         db,
         llm,
-        &config.interests_opml,
         &config.profile_path,
         config.curation.feedback.verdicts_in_prompt,
     )