feat(me): add mentions section for @-mentions in dashboard

Add a new --mentions flag to the `lore me` command that surfaces items
where the user is @-mentioned but NOT already assigned, authoring, or
reviewing. This fills an important gap in the personal work dashboard:
cross-team requests and callouts that don't show up in the standard
issue/MR sections.

Implementation details:
- query_mentioned_in() scans notes for @username patterns, then filters
  out entities where the user is already an assignee, author, or reviewer
- MentionedInItem type captures entity_type (issue/mr), iid, title, state,
  project path, attention state, and updated timestamp
- Attention state computation marks items as needs_attention when there's
  recent activity from others
- Recency cutoff (7 days) prevents surfacing stale mentions
- Both human and robot renderers include the new section

The robot mode schema adds mentioned_in array with me_mentions field
preset for token-efficient output.

Test coverage:
- mentioned_in_finds_mention_on_unassigned_issue: basic case
- mentioned_in_excludes_assigned_issue: no duplicate surfacing
- mentioned_in_excludes_author_on_mr: author already sees in authored MRs
- mentioned_in_excludes_reviewer_on_mr: reviewer already sees in reviewing
- mentioned_in_uses_recency_cutoff: old mentions filtered
- mentioned_in_respects_project_filter: scoping works

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/cli/commands/me/render_human.rs

@@ -1,8 +1,8 @@
 use crate::cli::render::{self, Align, GlyphMode, Icons, LoreRenderer, StyledCell, Table, Theme};
 
 use super::types::{
-    ActivityEventType, AttentionState, MeActivityEvent, MeDashboard, MeIssue, MeMr, MeSummary,
-    SinceLastCheck,
+    ActivityEventType, AttentionState, MeActivityEvent, MeDashboard, MeIssue, MeMention, MeMr,
+    MeSummary, SinceLastCheck,
 };
 
 // ─── Layout Helpers ─────────────────────────────────────────────────────────
@@ -164,12 +164,19 @@ pub fn print_summary_header(summary: &MeSummary, username: &str) {
         Theme::dim().render("0 need attention")
     };
 
+    let mentioned = if summary.mentioned_in_count > 0 {
+        format!("  {} mentioned", summary.mentioned_in_count)
+    } else {
+        String::new()
+    };
+
     println!(
-        "  {} projects  {} issues  {} authored MRs  {} reviewing MRs  {}",
+        "  {} projects  {} issues  {} authored MRs  {} reviewing MRs{}  {}",
         summary.project_count,
         summary.open_issue_count,
         summary.authored_mr_count,
         summary.reviewing_mr_count,
+        mentioned,
         needs,
     );
 
@@ -342,6 +349,53 @@ pub fn print_reviewing_mrs_section(mrs: &[MeMr], single_project: bool) {
     }
 }
 
+// ─── Mentioned In Section ────────────────────────────────────────────────
+
+/// Print the "Mentioned In" section for items where user is @mentioned but
+/// not assigned, authored, or reviewing.
+pub fn print_mentioned_in_section(mentions: &[MeMention], single_project: bool) {
+    if mentions.is_empty() {
+        return;
+    }
+
+    println!(
+        "{}",
+        render::section_divider(&format!("Mentioned In ({})", mentions.len()))
+    );
+
+    for item in mentions {
+        let attn = styled_attention(&item.attention_state);
+        let ref_str = match item.entity_type.as_str() {
+            "issue" => format!("#{}", item.iid),
+            "mr" => format!("!{}", item.iid),
+            _ => format!("{}:{}", item.entity_type, item.iid),
+        };
+        let ref_style = match item.entity_type.as_str() {
+            "issue" => Theme::issue_ref(),
+            "mr" => Theme::mr_ref(),
+            _ => Theme::bold(),
+        };
+        let state_tag = match item.state.as_str() {
+            "opened" => String::new(),
+            other => format!(" [{}]", other),
+        };
+        let time = render::format_relative_time(item.updated_at);
+
+        println!(
+            "    {} {}  {}{}  {}",
+            attn,
+            ref_style.render(&ref_str),
+            render::truncate(&item.title, title_width(43)),
+            Theme::dim().render(&state_tag),
+            Theme::dim().render(&time),
+        );
+
+        if !single_project {
+            println!("      {}", Theme::dim().render(&item.project_path));
+        }
+    }
+}
+
 // ─── Activity Feed ───────────────────────────────────────────────────────────
 
 /// Print the activity feed section (Task #17).
@@ -587,6 +641,7 @@ pub fn print_me_dashboard(dashboard: &MeDashboard, single_project: bool) {
     print_issues_section(&dashboard.open_issues, single_project);
     print_authored_mrs_section(&dashboard.open_mrs_authored, single_project);
     print_reviewing_mrs_section(&dashboard.reviewing_mrs, single_project);
+    print_mentioned_in_section(&dashboard.mentioned_in, single_project);
     print_activity_section(&dashboard.activity, single_project);
     println!();
 }
@@ -597,6 +652,7 @@ pub fn print_me_dashboard_filtered(
     single_project: bool,
     show_issues: bool,
     show_mrs: bool,
+    show_mentions: bool,
     show_activity: bool,
 ) {
     if let Some(ref since) = dashboard.since_last_check {
@@ -611,6 +667,9 @@ pub fn print_me_dashboard_filtered(
         print_authored_mrs_section(&dashboard.open_mrs_authored, single_project);
         print_reviewing_mrs_section(&dashboard.reviewing_mrs, single_project);
     }
+    if show_mentions {
+        print_mentioned_in_section(&dashboard.mentioned_in, single_project);
+    }
     if show_activity {
         print_activity_section(&dashboard.activity, single_project);
     }