feat(robot): add elapsed_ms timing, --fields support, and actionable error actions

Robot mode consistency improvements across all command output:

Timing:
- Every robot JSON response now includes meta.elapsed_ms measuring
  wall-clock time from command start to serialization. Agents can use
  this to detect slow queries and tune --limit or --project filters.

Field selection (--fields):
- print_list_issues_json and print_list_mrs_json accept an optional
  fields slice that prunes each item in the response array to only
  the requested keys. A "minimal" preset expands to
  [iid, title, state, updated_at_iso] for token-efficient agent scans.
- filter_fields and expand_fields_preset live in the new
  src/cli/robot.rs module alongside RobotMeta.

Actionable error recovery:
- LoreError gains an actions() method returning concrete shell commands
  an agent can execute to recover (e.g. "ollama serve" for
  OllamaUnavailable, "lore init" for ConfigNotFound).
- RobotError now serializes an "actions" array (empty array omitted)
  so agents can parse and offer one-click fixes.

Envelope consistency:
- show issue/MR JSON responses now use the standard
  {"ok":true,"data":...,"meta":...} envelope instead of bare data,
  matching all other commands.

Files: src/cli/robot.rs (new), src/core/error.rs,
       src/cli/commands/{count,embed,generate_docs,ingest,list,show,stats,sync_status}.rs

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

src/core/error.rs

@@ -239,11 +239,32 @@ impl LoreError {
         self.code().exit_code()
     }
 
+    pub fn actions(&self) -> Vec<&'static str> {
+        match self {
+            Self::ConfigNotFound { .. } => vec!["lore init"],
+            Self::ConfigInvalid { .. } => vec!["lore init --force"],
+            Self::GitLabAuthFailed => {
+                vec!["export GITLAB_TOKEN=glpat-xxx", "lore auth"]
+            }
+            Self::TokenNotSet { .. } => vec!["export GITLAB_TOKEN=glpat-xxx"],
+            Self::OllamaUnavailable { .. } => vec!["ollama serve"],
+            Self::OllamaModelNotFound { .. } => vec!["ollama pull nomic-embed-text"],
+            Self::DatabaseLocked { .. } => vec!["lore ingest --force"],
+            Self::EmbeddingsNotBuilt => vec!["lore embed"],
+            Self::EmbeddingFailed { .. } => vec!["lore embed --retry-failed"],
+            Self::MigrationFailed { .. } => vec!["lore migrate"],
+            Self::GitLabNetworkError { .. } => vec!["lore doctor"],
+            _ => vec![],
+        }
+    }
+
     pub fn to_robot_error(&self) -> RobotError {
+        let actions = self.actions().into_iter().map(String::from).collect();
         RobotError {
             code: self.code().to_string(),
             message: self.to_string(),
             suggestion: self.suggestion().map(String::from),
+            actions,
         }
     }
 }
@@ -254,6 +275,8 @@ pub struct RobotError {
     pub message: String,
     #[serde(skip_serializing_if = "Option::is_none")]
     pub suggestion: Option<String>,
+    #[serde(skip_serializing_if = "Vec::is_empty")]
+    pub actions: Vec<String>,
 }
 
 #[derive(Debug, Serialize)]