feat(timeline): upgrade seed phase to hybrid search

Replace FTS-only seed entity discovery with hybrid search (FTS + vector
via RRF), using the same search_hybrid infrastructure as the search
command. Falls back gracefully to FTS-only when Ollama is unavailable.

Changes:
- seed_timeline() now accepts OllamaClient, delegates to search_hybrid
- New resolve_documents_to_entities() replaces find_seed_entities()
- SeedResult gains search_mode field tracking actual mode used
- TimelineResult carries search_mode through to JSON renderer
- run_timeline wires up OllamaClient from config
- handle_timeline made async for the hybrid search await
- Tests updated for new function signatures

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

src/cli/commands/timeline.rs

@@ -13,6 +13,7 @@ use crate::core::timeline::{
 use crate::core::timeline_collect::collect_events;
 use crate::core::timeline_expand::expand_timeline;
 use crate::core::timeline_seed::seed_timeline;
+use crate::embedding::ollama::{OllamaClient, OllamaConfig};
 
 /// Parameters for running the timeline pipeline.
 pub struct TimelineParams {
@@ -28,7 +29,7 @@ pub struct TimelineParams {
 }
 
 /// Run the full timeline pipeline: SEED -> EXPAND -> COLLECT.
-pub fn run_timeline(config: &Config, params: &TimelineParams) -> Result<TimelineResult> {
+pub async fn run_timeline(config: &Config, params: &TimelineParams) -> Result<TimelineResult> {
     let db_path = get_db_path(config.storage.db_path.as_deref());
     let conn = create_connection(&db_path)?;
 
@@ -50,15 +51,25 @@ pub fn run_timeline(config: &Config, params: &TimelineParams) -> Result<Timeline
         })
         .transpose()?;
 
-    // Stage 1+2: SEED + HYDRATE
+    // Construct OllamaClient for hybrid search (same pattern as run_search)
+    let ollama_cfg = &config.embedding;
+    let client = OllamaClient::new(OllamaConfig {
+        base_url: ollama_cfg.base_url.clone(),
+        model: ollama_cfg.model.clone(),
+        ..OllamaConfig::default()
+    });
+
+    // Stage 1+2: SEED + HYDRATE (hybrid search with FTS fallback)
     let seed_result = seed_timeline(
         &conn,
+        Some(&client),
         &params.query,
         project_id,
         since_ms,
         params.max_seeds,
         params.max_evidence,
-    )?;
+    )
+    .await?;
 
     // Stage 3: EXPAND
     let expand_result = expand_timeline(
@@ -81,6 +92,7 @@ pub fn run_timeline(config: &Config, params: &TimelineParams) -> Result<Timeline
 
     Ok(TimelineResult {
         query: params.query.clone(),
+        search_mode: seed_result.search_mode,
         events,
         total_events_before_limit: total_before_limit,
         seed_entities: seed_result.seed_entities,
@@ -258,7 +270,7 @@ pub fn print_timeline_json_with_meta(
         ok: true,
         data: TimelineDataJson::from_result(result),
         meta: TimelineMetaJson {
-            search_mode: "lexical".to_owned(),
+            search_mode: result.search_mode.clone(),
             expansion_depth: depth,
             expand_mentions,
             total_entities: result.seed_entities.len() + result.expanded_entities.len(),