perf: round 20 — iCal/vCard parse allocs, owned-DTO moves, Result-collect pre-size, NC etag/favorites emit

Benchmark-gated (benches/ROUND20.md), same rule as rounds 2-19: every change
ships with a BEFORE/AFTER counting-allocator micro-benchmark and a byte-value
equivalence gate; a non-winning AFTER is rolled back (never applied). The
rollback rule is encoded in the harness (GATE FAIL exit). All 8 sections pass.

Reproduce: cargo run --release --features bench --example bench_round20_micro

- A1 CalendarEvent iCal parse: replace the throwaway per-property
  HashMap<String,Vec<String>> (DTSTART/DTEND/RECURRENCE-ID) with a direct
  VALUE=DATE scan; prop_with_params kept #[cfg(test)] (6->2 allocs/event, 4.2x)
- A2 UserDto::from: add User::into_parts and MOVE image (<=512 KiB data URI)
  + ui_preferences JSON instead of cloning on every /api/auth/me (27->14 allocs)
- A3 parse_vcard: drop the per-line to_ascii_uppercase copy + the lines Vec;
  promote ascii_ci_contains to common::text and share it (8->1 allocs/contact)
- A4 Calendar/AddressBook DTO: into_parts move incl. custom_properties map (18->10)
- I1 file-listing repos: collect::<Result<Vec>>() size-hints to 0 and grows from
  capacity 0; pre-size with Vec::with_capacity (8->1 container reallocs, 4 sites)
- I4 plaintext_stream: lazy emit iterator instead of eager Vec collect (43x wall)
- C1 NC write_etag_element: borrowed pre-escaped quote events, no owned quoted
  String/escape re-alloc; byte-identical output (3->0 allocs/PROPFIND row)
- C3 NC favorites REPORT: map.remove() move instead of get().clone() (~7 allocs/fav)

Deferred (documented in ROUND20.md): NC oc:id/trashbin buffer reuse, I1 sibling
CardDAV/CalDAV listing paths, Contact JSONB Json<Vec<_>> decode, dedup
settle_batch &str bind, and a fast DoS-resistant hasher for hot trusted-key maps
(needs a dependency decision).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01JsJjcVX9RoN96DMa35Wqzd

src/application/services/contact_service.rs

@@ -14,6 +14,7 @@ use crate::application::ports::carddav_ports::{
     AddressBookUseCase, ContactStoragePort, ContactUseCase,
 };
 use crate::common::errors::DomainError;
+use crate::common::text::ascii_ci_contains;
 use crate::domain::entities::contact::{Address, AddressBook, Contact, ContactGroup, Email, Phone};
 use crate::domain::services::authorization::{Permission, Resource, Role, Subject};
 use crate::infrastructure::adapters::contact_storage_adapter::ContactStorageAdapter;
@@ -113,9 +114,11 @@ impl ContactService {
 
         let mut contact = Contact::default();
 
-        let lines: Vec<&str> = vcard_data.lines().collect();
-
-        for line in &lines {
+        // Iterate lines() directly — the previous `Vec<&str>` collect was only
+        // ever iterated once. Per EMAIL/TEL/ADR line the `TYPE=` routing uses
+        // the allocation-free `ascii_ci_contains` instead of a throwaway
+        // `line.to_ascii_uppercase()` copy (benches/ROUND20.md §A3).
+        for line in vcard_data.lines() {
             let line = line.trim();
 
             if let Some(stripped) = line.strip_prefix("FN:") {
@@ -132,10 +135,10 @@ impl ContactService {
                 // from value parsing.
                 let value = line.split_once(':').map(|(_, v)| v.trim()).unwrap_or("");
                 if !value.is_empty() {
-                    let params_upper = line.to_ascii_uppercase();
-                    let email_type = if params_upper.contains("TYPE=HOME") {
+                    let lb = line.as_bytes();
+                    let email_type = if ascii_ci_contains(lb, b"TYPE=HOME") {
                         "home"
-                    } else if params_upper.contains("TYPE=WORK") {
+                    } else if ascii_ci_contains(lb, b"TYPE=WORK") {
                         "work"
                     } else {
                         "other"
@@ -167,16 +170,16 @@ impl ContactService {
                     // and dropped lowercase to "other" — matches
                     // the shape python-caldav / Apple Contacts
                     // emit.
-                    let params_upper = line.to_ascii_uppercase();
-                    let phone_type = if params_upper.contains("TYPE=CELL")
-                        || params_upper.contains("TYPE=MOBILE")
+                    let lb = line.as_bytes();
+                    let phone_type = if ascii_ci_contains(lb, b"TYPE=CELL")
+                        || ascii_ci_contains(lb, b"TYPE=MOBILE")
                     {
                         "mobile"
-                    } else if params_upper.contains("TYPE=HOME") {
+                    } else if ascii_ci_contains(lb, b"TYPE=HOME") {
                         "home"
-                    } else if params_upper.contains("TYPE=WORK") {
+                    } else if ascii_ci_contains(lb, b"TYPE=WORK") {
                         "work"
-                    } else if params_upper.contains("TYPE=FAX") {
+                    } else if ascii_ci_contains(lb, b"TYPE=FAX") {
                         "fax"
                     } else {
                         "other"
@@ -209,10 +212,10 @@ impl ContactService {
                         .map(|s| s.trim().to_string())
                         .filter(|s| !s.is_empty())
                 };
-                let params_upper = line.to_ascii_uppercase();
-                let addr_type = if params_upper.contains("TYPE=HOME") {
+                let lb = line.as_bytes();
+                let addr_type = if ascii_ci_contains(lb, b"TYPE=HOME") {
                     "home"
-                } else if params_upper.contains("TYPE=WORK") {
+                } else if ascii_ci_contains(lb, b"TYPE=WORK") {
                     "work"
                 } else {
                     "other"

src/application/services/search_service.rs

@@ -13,6 +13,7 @@ use crate::application::ports::content_index_ports::{ContentHitDto, ContentIndex
 use crate::application::ports::inbound::SearchUseCase;
 use crate::application::ports::storage_ports::FileReadPort;
 use crate::common::errors::Result;
+use crate::common::text::ascii_ci_contains;
 use crate::domain::entities::folder::Folder;
 use crate::domain::repositories::folder_repository::FolderRepository;
 use crate::infrastructure::repositories::pg::file_blob_read_repository::FileBlobReadRepository;
@@ -183,20 +184,6 @@ fn compute_relevance(name: &str, query_lower: &str) -> u32 {
     }
 }
 
-/// ASCII case-insensitive substring test — the allocation-free equivalent of
-/// `haystack_lower.contains(needle_lower)` when both are ASCII.
-fn ascii_ci_contains(haystack: &[u8], needle: &[u8]) -> bool {
-    if needle.is_empty() {
-        return true;
-    }
-    if needle.len() > haystack.len() {
-        return false;
-    }
-    haystack
-        .windows(needle.len())
-        .any(|w| w.eq_ignore_ascii_case(needle))
-}
-
 /// Max content-index candidates fetched per search. Hydration re-filters
 /// them in ONE SQL round-trip, so this bounds both index and DB work.
 const CONTENT_HITS_LIMIT: usize = 200;