refactor: Remove redundant doc comments throughout codebase

Removes module-level doc comments (//! lines) and excessive inline doc
comments that were duplicating information already evident from:
- Function/struct names (self-documenting code)
- Type signatures (the what is clear from types)
- Implementation context (the how is clear from code)

Affected modules:
- cli/* - Removed command descriptions duplicating clap help text
- core/* - Removed module headers and obvious function docs
- documents/* - Removed extractor/regenerator/truncation docs
- embedding/* - Removed pipeline and chunking docs
- gitlab/* - Removed client and transformer docs (kept type definitions)
- ingestion/* - Removed orchestrator and ingestion docs
- search/* - Removed FTS and vector search docs

Philosophy: Code should be self-documenting. Comments should explain
"why" (business decisions, non-obvious constraints) not "what" (which
the code itself shows). This change reduces noise and maintenance burden
while keeping the codebase just as understandable.

Retains comments for:
- Non-obvious business logic
- Important safety invariants
- Complex algorithm explanations
- Public API boundaries where generated docs matter

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

src/cli/commands/search.rs

@@ -1,5 +1,3 @@
-//! Search command: lexical (FTS5) search with filter support and single-query hydration.
-
 use console::style;
 use serde::Serialize;
 
@@ -15,7 +13,6 @@ use crate::search::{
     search_fts,
 };
 
-/// Display-ready search result with all fields hydrated.
 #[derive(Debug, Serialize)]
 pub struct SearchResultDisplay {
     pub document_id: i64,
@@ -34,7 +31,6 @@ pub struct SearchResultDisplay {
     pub explain: Option<ExplainData>,
 }
 
-/// Ranking explanation for --explain output.
 #[derive(Debug, Serialize)]
 pub struct ExplainData {
     pub vector_rank: Option<usize>,
@@ -42,7 +38,6 @@ pub struct ExplainData {
     pub rrf_score: f64,
 }
 
-/// Search response wrapper.
 #[derive(Debug, Serialize)]
 pub struct SearchResponse {
     pub query: String,
@@ -52,7 +47,6 @@ pub struct SearchResponse {
     pub warnings: Vec<String>,
 }
 
-/// Build SearchFilters from CLI args.
 pub struct SearchCliFilters {
     pub source_type: Option<String>,
     pub author: Option<String>,
@@ -64,7 +58,6 @@ pub struct SearchCliFilters {
     pub limit: usize,
 }
 
-/// Run a lexical search query.
 pub fn run_search(
     config: &Config,
     query: &str,
@@ -75,7 +68,6 @@ pub fn run_search(
     let db_path = get_db_path(config.storage.db_path.as_deref());
     let conn = create_connection(&db_path)?;
 
-    // Check if any documents exist
     let doc_count: i64 = conn
         .query_row("SELECT COUNT(*) FROM documents", [], |row| row.get(0))
         .unwrap_or(0);
@@ -90,7 +82,6 @@ pub fn run_search(
         });
     }
 
-    // Build filters
     let source_type = cli_filters
         .source_type
         .as_deref()
@@ -146,7 +137,6 @@ pub fn run_search(
         limit: cli_filters.limit,
     };
 
-    // Adaptive recall: wider initial fetch when filters applied
     let requested = filters.clamp_limit();
     let top_k = if filters.has_any_filter() {
         (requested * 50).clamp(200, 1500)
@@ -154,24 +144,20 @@ pub fn run_search(
         (requested * 10).clamp(50, 1500)
     };
 
-    // FTS search
     let fts_results = search_fts(&conn, query, top_k, fts_mode)?;
     let fts_tuples: Vec<(i64, f64)> = fts_results
         .iter()
         .map(|r| (r.document_id, r.bm25_score))
         .collect();
 
-    // Build snippet map before ranking
     let snippet_map: std::collections::HashMap<i64, String> = fts_results
         .iter()
         .map(|r| (r.document_id, r.snippet.clone()))
         .collect();
 
-    // RRF ranking (single-list for lexical mode)
     let ranked = rank_rrf(&[], &fts_tuples);
     let ranked_ids: Vec<i64> = ranked.iter().map(|r| r.document_id).collect();
 
-    // Apply post-retrieval filters
     let filtered_ids = apply_filters(&conn, &ranked_ids, &filters)?;
 
     if filtered_ids.is_empty() {
@@ -184,10 +170,8 @@ pub fn run_search(
         });
     }
 
-    // Hydrate results in single round-trip
     let hydrated = hydrate_results(&conn, &filtered_ids)?;
 
-    // Build display results preserving filter order
     let rrf_map: std::collections::HashMap<i64, &crate::search::RrfResult> =
         ranked.iter().map(|r| (r.document_id, r)).collect();
 
@@ -233,7 +217,6 @@ pub fn run_search(
     })
 }
 
-/// Raw row from hydration query.
 struct HydratedRow {
     document_id: i64,
     source_type: String,
@@ -248,10 +231,6 @@ struct HydratedRow {
     paths: Vec<String>,
 }
 
-/// Hydrate document IDs into full display rows in a single query.
-///
-/// Uses json_each() to pass ranked IDs and preserve ordering via ORDER BY j.key.
-/// Labels and paths fetched via correlated json_group_array subqueries.
 fn hydrate_results(conn: &rusqlite::Connection, document_ids: &[i64]) -> Result<Vec<HydratedRow>> {
     if document_ids.is_empty() {
         return Ok(Vec::new());
@@ -299,7 +278,6 @@ fn hydrate_results(conn: &rusqlite::Connection, document_ids: &[i64]) -> Result<
     Ok(rows)
 }
 
-/// Parse a JSON array string into a Vec<String>, filtering out null/empty.
 fn parse_json_array(json: &str) -> Vec<String> {
     serde_json::from_str::<Vec<serde_json::Value>>(json)
         .unwrap_or_default()
@@ -309,7 +287,6 @@ fn parse_json_array(json: &str) -> Vec<String> {
         .collect()
 }
 
-/// Print human-readable search results.
 pub fn print_search_results(response: &SearchResponse) {
     if !response.warnings.is_empty() {
         for w in &response.warnings {
@@ -364,7 +341,6 @@ pub fn print_search_results(response: &SearchResponse) {
             println!("    Labels: {}", result.labels.join(", "));
         }
 
-        // Strip HTML tags from snippet for terminal display
         let clean_snippet = result.snippet.replace("<mark>", "").replace("</mark>", "");
         println!("    {}", style(clean_snippet).dim());
 
@@ -384,7 +360,6 @@ pub fn print_search_results(response: &SearchResponse) {
     }
 }
 
-/// JSON output structures.
 #[derive(Serialize)]
 struct SearchJsonOutput<'a> {
     ok: bool,
@@ -397,7 +372,6 @@ struct SearchMeta {
     elapsed_ms: u64,
 }
 
-/// Print JSON robot-mode output.
 pub fn print_search_results_json(response: &SearchResponse, elapsed_ms: u64) {
     let output = SearchJsonOutput {
         ok: true,