chore(release): 0.4.0

[github-actions]

The next claudecode.nvim release. Merging this PR creates the release tag and GitHub Release, then starts Communique GitHub Release note generation.

[0.4.0] - 2026-06-15

Added

• :checkhealth claudecode health check that verifies your setup end to end: Neovim version, setup() invocation, Claude CLI resolution and version, terminal provider sanity, WebSocket server/port, lock file presence, and live client connection state (#275).
• :ClaudeCodeSendText {text} command (and require("claudecode.terminal").send_to_terminal(text, opts)) to send arbitrary text to the open Claude terminal as if typed at the prompt, submitting by default; :ClaudeCodeSendText! inserts without submitting. Multi-line text is sent via bracketed paste. Works with the in-editor native/snacks providers only (#197, #272).
• :ClaudeCodeCloseAllDiffs command to close all pending Claude diffs at once. Diffs already accepted but not yet written are preserved (#248, #261).
• User ClaudeCodeSendComplete autocmd, fired once per file when a send is accepted while Claude is connected, with data = { file_path, start_line, end_line, context }. Lets you run post-send logic such as focusing a Claude session running outside Neovim (#228, #265).
• User ClaudeCodeDiffOpened / ClaudeCodeDiffClosed autocmds carrying a data payload, so configs can react to diffs opening and closing without monkey-patching internals (#270).
• terminal.diff_split_width_percentage to set a distinct terminal width while a diff is open, and diff_opts.auto_resize_terminal (default true) to opt out of width changes entirely so you can own the layout (#270).
• netrw file selection: <leader>as in a netrw buffer adds marked files (or the file under the cursor) to Claude's context (#62).
• snacks.nvim picker support for :ClaudeCodeTreeAdd/:ClaudeCodeSend: with a snacks picker list focused, add the selected/highlighted file(s) to Claude's context (#192, #269).

Changed

• Modernized the :ClaudeCodeSelectModel picker with evergreen, version-free labels (Claude Opus (Latest), Claude Sonnet (Latest), Claude Haiku (Latest)), added 1M-context variants (opus[1m], sonnet[1m]) and a Default (account recommended) entry (#256).

Fixed

• Snacks launch failure: model aliases containing [ ] (the 1M variants) were passed to the shell and aborted with zsh: no matches found. The Snacks provider now launches Claude via an argv list with no shell interpretation (#256).
• Legacy diff options vertical_split and open_in_current_tab were silently ignored due to merge order; they now map correctly to layout/open_in_new_tab (#142).
• False keepalive disconnects after system sleep: client pong timestamps are reset on detecting a wake event so clients aren't dropped on resume (#141).
• IDE response handling: getDiagnostics now returns grouped URI-based payloads with editor-native ranges and severity names; the server no longer advertises an unsupported resources capability; background file opens preserve focus and return target-buffer metadata (#274).
• getDiagnostics no longer errors when Claude passes a bare file path instead of a file:// URI (#163).
• Auth token is now generated from a CSPRNG (libuv//dev/urandom), the lock file is written atomically with mode 0600, and the IDE directory is created with mode 0700 (previously world-readable). Handshake auth comparison is now constant-time (#259).
• Malformed WebSocket frames now close the connection with the proper RFC 6455 status code (1002/1007/1009) instead of wedging the connection and re-parsing bad bytes forever (#258, #257).
• TCP disconnects now reliably fire on_disconnect for EOF, read errors, protocol errors, CLOSE frames, and keepalive timeouts, fixing phantom/stale client entries (#176, #170).
• The Claude terminal now adds loopback hosts to no_proxy/NO_PROXY, so a configured proxy no longer tunnels Claude's ws://127.0.0.1 IDE connection and times out @ mentions; existing exclusions are preserved (#70, #268).
• Worked around a Neovim core bug (< 0.12.2) that fragmented large bracketed pastes, making Cmd+V appear to truncate content; controlled by terminal.fix_streamed_paste ("auto" by default) (#252).
• Rejecting a diff with :q (or :close/<C-w>c/closing the tab) now resolves it as rejected via a new WinClosed handler (#266).
• Quickly-made and single-line visual selections are now flushed synchronously on visual-mode exit and persist until the cursor moves, so they reliably reach Claude (#246, #267).
• Selection context is now also sent on BufEnter so switching buffers updates Claude even without cursor movement (#159), and the provider = "none" fallback now matches the Claude terminal name as a substring (#160).
• Selection debounce timers are now stopped and closed via the libuv timer API, fixing leaked handles and stale callbacks firing after being superseded (#245).
• Pending diffs are now auto-closed when the client that opened them disconnects or the integration stops; closeAllDiffTabs also resolves the diff module's tracked state (#248, #261).
• Diffs now open when the Claude terminal is the only window (a split is created) instead of failing with "No suitable editor window found" (#231, #260).
• The Snacks Explorer sidebar (snacks_layout_box) and snacks pickers (snacks_picker_list) are now excluded from main-editor-window detection, so diffs no longer open into or corrupt the explorer (#236, #255, #165).
• diff_opts.keep_terminal_focus = true now works for floating Claude terminals (#150, #178).
• Plugin-created diff splits are now closed deterministically on cleanup, and stranded tabs from failed open_in_new_tab diff setup are closed (#155, #175, #264).
• The Snacks terminal "climbing cursor" on hide/show toggle is fixed; the provider now hides/shows without destroying the window. Splits are fixed on all supported Neovim versions; the float fix requires Neovim >= 0.10 (#240, #183, #271).
• focus_after_send = true now emits a one-time warning at setup with the none/external providers (which run Claude outside Neovim and cannot be focused), pointing to the User ClaudeCodeSendComplete autocmd (#228, #265).

Documentation

• The recommended lazy.nvim spec now declares cmd = { ... } so :ClaudeCode loads on demand from a cold start (#239, #263).
• Added IDE launch instructions for provider = "none" (#157).

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Maintained by the release-please workflow. CHANGELOG.md and the release PR body are regenerated by Communique on every push to main, so manual edits to this PR are overwritten.