refactor(robot): add constructors to RobotMeta, support optional gitlab_base_url

RobotMeta previously required direct struct literal construction with only
elapsed_ms. This made it impossible to add optional fields without updating
every call site to include them.

Introduce two constructors:
- RobotMeta::new(elapsed_ms) — standard meta with timing only
- RobotMeta::with_base_url(elapsed_ms, base_url) — meta enriched with the
  GitLab instance URL, enabling consumers to construct entity links without
  needing config access

The gitlab_base_url field uses #[serde(skip_serializing_if = "Option::is_none")]
so existing JSON envelopes are byte-identical — no breaking change for any
robot mode consumer.

All 22 call sites across handlers, count, cron, drift, embed, generate_docs,
ingest, list (mrs/notes), related, show, stats, sync_status, and who are
updated from struct literals to RobotMeta::new(). Three tests verify the
new constructors and trailing-slash normalization.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/cli/commands/count.rs

@@ -254,7 +254,7 @@ pub fn print_event_count_json(counts: &EventCounts, elapsed_ms: u64) {
             },
             total: counts.total(),
         },
-        meta: RobotMeta { elapsed_ms },
+        meta: RobotMeta::new(elapsed_ms),
     };
 
     match serde_json::to_string(&output) {
@@ -325,7 +325,7 @@ pub fn print_count_json(result: &CountResult, elapsed_ms: u64) {
             system_excluded: result.system_count,
             breakdown,
         },
-        meta: RobotMeta { elapsed_ms },
+        meta: RobotMeta::new(elapsed_ms),
     };
 
     match serde_json::to_string(&output) {

src/cli/commands/cron.rs

@@ -80,7 +80,7 @@ pub fn print_cron_install_json(result: &CronInstallResult, elapsed_ms: u64) {
             log_path: result.log_path.display().to_string(),
             replaced: result.replaced,
         },
-        meta: RobotMeta { elapsed_ms },
+        meta: RobotMeta::new(elapsed_ms),
     };
     if let Ok(json) = serde_json::to_string(&output) {
         println!("{json}");
@@ -128,7 +128,7 @@ pub fn print_cron_uninstall_json(result: &CronUninstallResult, elapsed_ms: u64)
             action: "uninstall",
             was_installed: result.was_installed,
         },
-        meta: RobotMeta { elapsed_ms },
+        meta: RobotMeta::new(elapsed_ms),
     };
     if let Ok(json) = serde_json::to_string(&output) {
         println!("{json}");
@@ -284,7 +284,7 @@ pub fn print_cron_status_json(info: &CronStatusInfo, elapsed_ms: u64) {
             last_sync_at: info.last_sync.as_ref().map(|s| s.started_at_iso.clone()),
             last_sync_status: info.last_sync.as_ref().map(|s| s.status.clone()),
         },
-        meta: RobotMeta { elapsed_ms },
+        meta: RobotMeta::new(elapsed_ms),
     };
     if let Ok(json) = serde_json::to_string(&output) {
         println!("{json}");

src/cli/commands/drift.rs

@@ -468,7 +468,7 @@ pub fn print_drift_human(response: &DriftResponse) {
 }
 
 pub fn print_drift_json(response: &DriftResponse, elapsed_ms: u64) {
-    let meta = RobotMeta { elapsed_ms };
+    let meta = RobotMeta::new(elapsed_ms);
     let output = serde_json::json!({
         "ok": true,
         "data": response,

src/cli/commands/embed.rs

@@ -135,7 +135,7 @@ pub fn print_embed_json(result: &EmbedCommandResult, elapsed_ms: u64) {
     let output = EmbedJsonOutput {
         ok: true,
         data: result,
-        meta: RobotMeta { elapsed_ms },
+        meta: RobotMeta::new(elapsed_ms),
     };
     match serde_json::to_string(&output) {
         Ok(json) => println!("{json}"),

src/cli/commands/generate_docs.rs

@@ -257,7 +257,7 @@ pub fn print_generate_docs_json(result: &GenerateDocsResult, elapsed_ms: u64) {
             unchanged: result.unchanged,
             errored: result.errored,
         },
-        meta: RobotMeta { elapsed_ms },
+        meta: RobotMeta::new(elapsed_ms),
     };
     match serde_json::to_string(&output) {
         Ok(json) => println!("{json}"),

src/cli/commands/ingest/render.rs

@@ -191,7 +191,7 @@ pub fn print_ingest_summary_json(result: &IngestResult, elapsed_ms: u64) {
             status_enrichment,
             status_enrichment_errors: result.status_enrichment_errors,
         },
-        meta: RobotMeta { elapsed_ms },
+        meta: RobotMeta::new(elapsed_ms),
     };
 
     match serde_json::to_string(&output) {

src/cli/commands/list/mrs.rs

@@ -370,7 +370,7 @@ pub fn print_list_mrs(result: &MrListResult) {
 
 pub fn print_list_mrs_json(result: &MrListResult, elapsed_ms: u64, fields: Option<&[String]>) {
     let json_result = MrListResultJson::from(result);
-    let meta = RobotMeta { elapsed_ms };
+    let meta = RobotMeta::new(elapsed_ms);
     let output = serde_json::json!({
         "ok": true,
         "data": json_result,

src/cli/commands/list/notes.rs

@@ -193,7 +193,7 @@ pub fn print_list_notes(result: &NoteListResult) {
 
 pub fn print_list_notes_json(result: &NoteListResult, elapsed_ms: u64, fields: Option<&[String]>) {
     let json_result = NoteListResultJson::from(result);
-    let meta = RobotMeta { elapsed_ms };
+    let meta = RobotMeta::new(elapsed_ms);
     let output = serde_json::json!({
         "ok": true,
         "data": json_result,

src/cli/commands/related.rs

@@ -558,7 +558,7 @@ pub fn print_related_human(response: &RelatedResponse) {
 }
 
 pub fn print_related_json(response: &RelatedResponse, elapsed_ms: u64) {
-    let meta = RobotMeta { elapsed_ms };
+    let meta = RobotMeta::new(elapsed_ms);
     let output = serde_json::json!({
         "ok": true,
         "data": response,

src/cli/commands/show/render.rs

@@ -557,7 +557,7 @@ impl From<&MrNoteDetail> for MrNoteDetailJson {
 
 pub fn print_show_issue_json(issue: &IssueDetail, elapsed_ms: u64) {
     let json_result = IssueDetailJson::from(issue);
-    let meta = RobotMeta { elapsed_ms };
+    let meta = RobotMeta::new(elapsed_ms);
     let output = serde_json::json!({
         "ok": true,
         "data": json_result,
@@ -571,7 +571,7 @@ pub fn print_show_issue_json(issue: &IssueDetail, elapsed_ms: u64) {
 
 pub fn print_show_mr_json(mr: &MrDetail, elapsed_ms: u64) {
     let json_result = MrDetailJson::from(mr);
-    let meta = RobotMeta { elapsed_ms };
+    let meta = RobotMeta::new(elapsed_ms);
     let output = serde_json::json!({
         "ok": true,
         "data": json_result,

src/cli/commands/stats.rs

@@ -583,7 +583,7 @@ pub fn print_stats_json(result: &StatsResult, elapsed_ms: u64) {
                 }),
             }),
         },
-        meta: RobotMeta { elapsed_ms },
+        meta: RobotMeta::new(elapsed_ms),
     };
     match serde_json::to_string(&output) {
         Ok(json) => println!("{json}"),

src/cli/commands/sync_status.rs

@@ -313,7 +313,7 @@ pub fn print_sync_status_json(result: &SyncStatusResult, elapsed_ms: u64) {
                 system_notes: result.summary.system_note_count,
             },
         },
-        meta: RobotMeta { elapsed_ms },
+        meta: RobotMeta::new(elapsed_ms),
     };
 
     match serde_json::to_string(&output) {

src/cli/commands/who/mod.rs

@@ -376,7 +376,7 @@ pub fn print_who_json(run: &WhoRun, args: &WhoArgs, elapsed_ms: u64) {
             resolved_input,
             result: data,
         },
-        meta: RobotMeta { elapsed_ms },
+        meta: RobotMeta::new(elapsed_ms),
     };
 
     let mut value = serde_json::to_value(&output).unwrap_or_else(|e| {