chore: cargo fmt + clippy --fix sweep across the crate

Pure mechanical cleanup of accumulated drift in files outside the
HLS-content-hash branch's main change set. No behavior change.

- `cargo fmt` on every previously-misformatted file
  (`ai/insight_generator.rs`, `database/knowledge_dao.rs`,
  `faces.rs`, `knowledge.rs`, `libraries.rs`).
- `cargo clippy --fix`:
  - `needless_borrow`: `&library` → `library` in `handlers/image.rs`
    (two sites in the photo-listing path).
- Manual clippy pass for warnings clippy emits but can't auto-apply:
  - `field_reassign_with_default` in `database/reconcile.rs::run` —
    consolidated into a struct-literal initializer.
  - `needless_range_loop` in `database/knowledge_dao.rs::union_perceptual_tags`
    — inner `for b in (a+1)..indices.len() { let ib = indices[b]; ... }`
    becomes `for &ib in &indices[a + 1..] { ... }`.
  - Doc-list indentation: continuation lines under nested bullets in
    `database/mod.rs::get_memories_in_window` and
    `database/knowledge_dao.rs::build_entity_graph` realigned to the
    list-item content column.

Deliberately not touched (each deserves its own focused commit, with
testing, rather than getting bundled into a sweep):
- 4× `deprecated count_distinct` in `faces.rs` — diesel API migration
  to `AggregateExpressionMethods::aggregate_distinct` may shift result
  types; needs verification against the existing stats queries.
- `await_holding_lock` in `knowledge.rs:807` — `std::sync::Mutex` held
  across `ollama.generate(...).await`. Genuine concurrency bug; fix
  requires understanding the surrounding flow before just dropping
  the guard.
- 2× `type_complexity` in `database/mod.rs` — cosmetic, would need a
  `type` alias and corresponding callers updated.
- Dead `total_deleted` on `library_maintenance::GcStats` and
  `file_scan::enumerate_indexable_files` — both are public surface
  retained for future use; deletion is a separate decision.

All 707 tests still pass. Release build clean.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/database/knowledge_dao.rs

@@ -235,6 +235,7 @@ pub trait KnowledgeDao: Sync + Send {
     ///   - entity_type: optional, restricts nodes to one type
     ///   - node_limit: caps the number of nodes; lower-fact-count
     ///     entities drop first
+    ///
     /// Edges between dropped entities are pruned. Persona scoping
     /// affects fact_count + edge inclusion (rejected / superseded
     /// excluded; All vs Single mirrors the existing pattern).
@@ -937,7 +938,10 @@ impl KnowledgeDao for SqliteKnowledgeDao {
             let mut conn = self.connection.lock().expect("KnowledgeDao lock");
             let mut q = sql_query(sql).into_boxed();
             match persona {
-                PersonaFilter::Single { user_id, persona_id } => {
+                PersonaFilter::Single {
+                    user_id,
+                    persona_id,
+                } => {
                     q = q
                         .bind::<Integer, _>(*user_id)
                         .bind::<Text, _>(persona_id.clone());
@@ -977,7 +981,10 @@ impl KnowledgeDao for SqliteKnowledgeDao {
             // rows flip — REVIEWED survives so the curator can preserve
             // a hand-approved exception under the same predicate.
             let touched = match persona {
-                PersonaFilter::Single { user_id: uid, persona_id: pid } => diesel::update(
+                PersonaFilter::Single {
+                    user_id: uid,
+                    persona_id: pid,
+                } => diesel::update(
                     entity_facts
                         .filter(predicate.eq(target_predicate))
                         .filter(user_id.eq(*uid))
@@ -1282,8 +1289,7 @@ impl KnowledgeDao for SqliteKnowledgeDao {
                         Some(v) => v,
                         None => continue,
                     };
-                    for b in (a + 1)..indices.len() {
-                        let ib = indices[b];
+                    for &ib in &indices[a + 1..] {
                         let vb = match &decoded[ib] {
                             Some(v) => v,
                             None => continue,