refactor(search): rename --after/--updated-after to --since/--updated-since

The --since naming is more intuitive (matches git log --since) and
consistent with the list commands which already use --since. Renames
the CLI flags, SearchCliFilters fields, SearchFilters fields,
autocorrect registry, and robot-docs manifest. No behavioral change.

Affected paths:
- cli/mod.rs: SearchArgs field + clap attribute rename
- cli/commands/search.rs: SearchCliFilters + run_search plumbing
- search/filters.rs: SearchFilters struct + apply_filters logic
- main.rs: handle_search + robot-docs JSON
- cli/autocorrect.rs: COMMAND_FLAGS entry for search

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

src/cli/commands/search.rs

@@ -53,8 +53,8 @@ pub struct SearchCliFilters {
     pub project: Option<String>,
     pub labels: Vec<String>,
     pub path: Option<String>,
-    pub after: Option<String>,
-    pub updated_after: Option<String>,
+    pub since: Option<String>,
+    pub updated_since: Option<String>,
     pub limit: usize,
 }
 
@@ -63,22 +63,36 @@ pub fn run_search(
     query: &str,
     cli_filters: SearchCliFilters,
     fts_mode: FtsQueryMode,
+    requested_mode: &str,
     explain: bool,
 ) -> Result<SearchResponse> {
     let db_path = get_db_path(config.storage.db_path.as_deref());
     let conn = create_connection(&db_path)?;
 
+    let mut warnings: Vec<String> = Vec::new();
+
+    // Determine actual mode: vector search requires embeddings, which need async + Ollama.
+    // Until hybrid/semantic are wired up, we run lexical and warn if the user asked for more.
+    let actual_mode = "lexical";
+    if requested_mode != "lexical" {
+        warnings.push(format!(
+            "Requested mode '{}' is not yet available; falling back to lexical search.",
+            requested_mode
+        ));
+    }
+
     let doc_count: i64 = conn
         .query_row("SELECT COUNT(*) FROM documents", [], |row| row.get(0))
         .unwrap_or(0);
 
     if doc_count == 0 {
+        warnings.push("No documents indexed. Run 'lore generate-docs' first.".to_string());
         return Ok(SearchResponse {
             query: query.to_string(),
-            mode: "lexical".to_string(),
+            mode: actual_mode.to_string(),
             total_results: 0,
             results: vec![],
-            warnings: vec!["No documents indexed. Run 'lore generate-docs' first.".to_string()],
+            warnings,
         });
     }
 
@@ -93,25 +107,25 @@ pub fn run_search(
         .map(|p| resolve_project(&conn, p))
         .transpose()?;
 
-    let after = cli_filters
-        .after
+    let since = cli_filters
+        .since
         .as_deref()
         .map(|s| {
             parse_since(s).ok_or_else(|| {
                 LoreError::Other(format!(
-                    "Invalid --after value '{}'. Use relative (7d, 2w, 1m) or absolute (YYYY-MM-DD) format.",
+                    "Invalid --since value '{}'. Use relative (7d, 2w, 1m) or absolute (YYYY-MM-DD) format.",
                     s
                 ))
             })
         })
         .transpose()?;
-    let updated_after = cli_filters
-        .updated_after
+    let updated_since = cli_filters
+        .updated_since
         .as_deref()
         .map(|s| {
             parse_since(s).ok_or_else(|| {
                 LoreError::Other(format!(
-                    "Invalid --updated-after value '{}'. Use relative (7d, 2w, 1m) or absolute (YYYY-MM-DD) format.",
+                    "Invalid --updated-since value '{}'. Use relative (7d, 2w, 1m) or absolute (YYYY-MM-DD) format.",
                     s
                 ))
             })
@@ -130,8 +144,8 @@ pub fn run_search(
         source_type,
         author: cli_filters.author,
         project_id,
-        after,
-        updated_after,
+        since,
+        updated_since,
         labels: cli_filters.labels,
         path,
         limit: cli_filters.limit,
@@ -163,10 +177,10 @@ pub fn run_search(
     if filtered_ids.is_empty() {
         return Ok(SearchResponse {
             query: query.to_string(),
-            mode: "lexical".to_string(),
+            mode: actual_mode.to_string(),
             total_results: 0,
             results: vec![],
-            warnings: vec![],
+            warnings,
         });
     }
 
@@ -210,10 +224,10 @@ pub fn run_search(
 
     Ok(SearchResponse {
         query: query.to_string(),
-        mode: "lexical".to_string(),
+        mode: actual_mode.to_string(),
         total_results: results.len(),
         results,
-        warnings: vec![],
+        warnings,
     })
 }