Release v0.6.28: typo correction, partial sync and selection diagnostics

README.md

@@ -336,7 +336,14 @@ the executable's directory is not writable. Each clipboard payload is an encrypt
 only bounded previews/metadata stay in memory. Image data is loaded on demand and released when
 the history popup is hidden. Settings **Write log** (`writeLog`, enabled by default) controls all
 log writes. Disabling it also clears diagnostic context from memory; existing log files remain.
-Diagnostic stages stay in a memory buffer of at most 40 events for 30 seconds.
+Diagnostic stages stay in a memory buffer of at most 128 events for 30 seconds.
+Selection diagnostics include the expected text, each copied candidate before and after suffix
+recovery, paced Shift+Left progress or batch delivery counts, and clipboard sequence changes,
+retry counts and elapsed times. Focus, caret geometry and keyboard layout are recorded when
+Windows exposes them; selection offsets are available for native EDIT controls and explicitly
+marked unavailable for other editors. Input interruptions identify keyboard, mouse, settings
+or layout-refresh events during an operation. Failed selection verification includes the expected
+selection and actual copied text in the operation details, without implying that a paste occurred.
 Only problem operations write a structured summary to `kswitcher.log`, with their preceding
 context. Successful operations stay in that bounded memory buffer and are included only when
 a subsequent problem flushes it; they do not create separate rows. Flushed context is discarded. Ordinary application
@@ -404,6 +411,10 @@ reverse-proxy URL prefixes, MFA login flows and other providers are not implemen
 
 Enable synchronization and choose **Save / Sign in / Sync**. The dialog saves connection changes
 immediately; the main Settings window's Save/Cancel does not control this separate configuration.
+When synchronization is disabled, connection fields and sync actions are inactive. Check **Enable
+synchronization** to make them available. To disable an existing connection, uncheck it and click
+**Save**; this preserves the saved connection and password without starting a sync request.
+**Disconnect / forget password** remains available while synchronization is disabled.
 A blank password keeps the existing Windows credential for that server, login mount and username.
 The password is saved in Windows Credential Manager, not in settings exports, logs or the remote
 profile. HTTPS certificate validation is mandatory and redirects are refused. Login tokens are
@@ -414,11 +425,15 @@ saved credential. A request already sent to the server may still complete; its d
 will not be applied after the connection changes. Old credentials for other connection identities
 can be removed in Windows Credential Manager under `KSwitcher.Sync/`.
 
-First connection is deliberately explicit:
+On the first connection, **Save / Sign in / Sync** merges the existing profiles without
+requiring a whole-profile replacement. Independent entries (such as snippets, exclusions and
+replacement pairs) are combined. Different values for the same setting remain on their respective
+sides and appear in **Resolve individual conflicts...**; no value is guessed without a common history.
+Nonconflicting changes synchronize immediately, and unresolved conflicts survive subsequent syncs.
 
 - **Upload local** creates the remote profile or replaces it with this PC's saved shared settings.
 - **Download remote** replaces this PC's shared settings with the server profile.
-- If both profiles are identical, ordinary Sync can establish the baseline without a replacement.
+- If the server has no profile yet, choose **Upload local** to create it.
 - Unsaved edits in Settings are not synchronized. Close and reopen Settings after a download;
   the existing stale-editor check prevents an old Settings window overwriting downloaded changes.
 
@@ -453,8 +468,14 @@ Deleted server versions are not silently recreated.
 Hotkeys, snippets, application exclusions, layout order, conversion, screenshot and autocorrection
 preferences are shared. Startup/elevation, keep-awake, logging, history enablement/limits,
 Tesseract executable/engine selection, connection details and credentials stay local. Clipboard
-history, screenshots and dictionary files are never uploaded. Missing keyboard layouts block
-applying a remote profile until those Windows layouts are installed, preventing lost bindings.
+history, screenshots and dictionary files are never uploaded. Full synchronization identifies
+missing keyboard layouts by language (when Windows can identify it) and exact ID.
+Install the same layout variant, or select **Keep this PC's layouts and layout shortcuts (sync
+other settings)** and click **Save / Sign in / Sync**. This device-local option keeps the entire
+local layout cycle and its direct shortcuts unchanged while synchronizing the other shared settings.
+The server's layout cycle and direct shortcuts are preserved on automatic sync and explicit Upload;
+Download also keeps the local layout configuration. Later syncs cannot erase missing server layouts
+just because this PC does not have them installed. Uncheck the option to resume full layout sync.
 Settings are JSON inside OpenBao; this is not end-to-end encryption from the vault administrator.
 
 The last common profile (`sync-base.bin`) and the settings preceding the most recent downloaded
@@ -506,13 +527,40 @@ Alternatively open this directory as a CMake project in Visual Studio with the C
 and Windows SDK installed, or use CMake with a Windows GCC toolchain. CMake/MSVC is provided but the
 verified local build uses GCC/w64devkit.
 
-## Automatic layout correction (experimental)
+## Automatic correction (experimental)
 
-Enable **Automatically correct layout (experimental)** in Settings, then use **Auto-correction
+Enable **Automatic correction (experimental)** in Settings, then use **Auto-correction
 options…** to select dictionary languages and edit excluded applications or words to never correct.
 The feature is off by default. English and Ukrainian are selected initially; Russian is optional.
 Target layouts must also be enabled in the layout cycle.
 
+### Custom replacements and spelling typos
+
+Two optional modes in **Auto-correction options…** extend layout correction. Both are off by
+default and require the main **Automatic correction (experimental)** checkbox to be enabled.
+
+- **Use custom replacements**: enter one `typo=correction` pair per line, for example
+  `првиіт=привіт` or `helo=hello`. Entries are normalized to lowercase; duplicate source words
+  are rejected. Each side must contain 1–32 letters of the same supported language, without
+  spaces or punctuation. Explicit pairs take priority over dictionary recognition, including
+  already valid words, and do not require dictionary membership or satisfy the frequency limit.
+- **Correct spelling typos using dictionaries**: checks unknown words in the current language
+  after no layout correction is found. It accepts exactly one dictionary candidate reachable
+  by inserting, deleting or replacing one letter, or swapping two adjacent letters. Both input
+  and target must have at least four letters. Multiple candidates leave the input unchanged,
+  even if a frequency limit would exclude one of them. Personal dictionary words participate.
+  This is word-level spelling correction, not grammar or sentence-context correction.
+
+Both modes run after Space, preserve surrounding punctuation and an initial capital, and keep
+the current layout. The selected dictionary languages, enabled layout cycle, minimum input
+length, excluded applications, never-correct list, protected fields and Undo behavior apply.
+ALL CAPS, mixed-case identifiers, numbers, URLs and email addresses are skipped. A replacement
+is applied once, without chaining. Click **OK**, then **Save** in Settings; pairs and switches
+are included in settings export/import and synchronization. Undo restores the original word
+and suppresses its correction until restart.
+
+### Layout correction and shared options
+
 **Characters before a word** and **Characters after a word** configure punctuation to preserve around
 the corrected word. Enter characters directly, without spaces or separators; a comma or semicolon
 is itself a character. Defaults include parentheses, square/curly brackets, quotation marks and common