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/core/events_db.rs

@@ -1,15 +1,9 @@
-//! Database upsert functions for resource events (state, label, milestone).
-
 use rusqlite::Connection;
 
 use super::error::{LoreError, Result};
 use super::time::iso_to_ms_strict;
 use crate::gitlab::types::{GitLabLabelEvent, GitLabMilestoneEvent, GitLabStateEvent};
 
-/// Upsert state events for an entity.
-///
-/// Uses INSERT OR REPLACE keyed on UNIQUE(gitlab_id, project_id).
-/// Caller is responsible for wrapping in a transaction if atomicity is needed.
 pub fn upsert_state_events(
     conn: &Connection,
     project_id: i64,
@@ -52,8 +46,6 @@ pub fn upsert_state_events(
     Ok(count)
 }
 
-/// Upsert label events for an entity.
-/// Caller is responsible for wrapping in a transaction if atomicity is needed.
 pub fn upsert_label_events(
     conn: &Connection,
     project_id: i64,
@@ -93,8 +85,6 @@ pub fn upsert_label_events(
     Ok(count)
 }
 
-/// Upsert milestone events for an entity.
-/// Caller is responsible for wrapping in a transaction if atomicity is needed.
 pub fn upsert_milestone_events(
     conn: &Connection,
     project_id: i64,
@@ -135,8 +125,6 @@ pub fn upsert_milestone_events(
     Ok(count)
 }
 
-/// Resolve entity type string to (issue_id, merge_request_id) pair.
-/// Exactly one is Some, the other is None.
 fn resolve_entity_ids(
     entity_type: &str,
     entity_local_id: i64,
@@ -150,11 +138,9 @@ fn resolve_entity_ids(
     }
 }
 
-/// Count resource events by type for the count command.
 pub fn count_events(conn: &Connection) -> Result<EventCounts> {
     let mut counts = EventCounts::default();
 
-    // State events
     let row: (i64, i64) = conn
         .query_row(
             "SELECT
@@ -168,7 +154,6 @@ pub fn count_events(conn: &Connection) -> Result<EventCounts> {
     counts.state_issue = row.0 as usize;
     counts.state_mr = row.1 as usize;
 
-    // Label events
     let row: (i64, i64) = conn
         .query_row(
             "SELECT
@@ -182,7 +167,6 @@ pub fn count_events(conn: &Connection) -> Result<EventCounts> {
     counts.label_issue = row.0 as usize;
     counts.label_mr = row.1 as usize;
 
-    // Milestone events
     let row: (i64, i64) = conn
         .query_row(
             "SELECT
@@ -199,7 +183,6 @@ pub fn count_events(conn: &Connection) -> Result<EventCounts> {
     Ok(counts)
 }
 
-/// Event counts broken down by type and entity.
 #[derive(Debug, Default)]
 pub struct EventCounts {
     pub state_issue: usize,