refactor(integrations): five hygiene fixes from the module-by-module re-review

- markdown-config.el: two related fixes on `markdown-preview'.
  First, the URL was `https://localhost:8080/imp' but simple-httpd
  serves plaintext on port 8080 -- the browser hit a TLS handshake
  against a non-TLS listener and the preview never rendered.  Changed
  to `http://' and switched from `browse-url-generic' to plain
  `browse-url' so the user's default protocol handler picks the
  browser.  Second, the function used to start the network listener
  as a side effect of opening a preview; that's split into a
  separate `cj/markdown-preview-server-start' command and
  `markdown-preview' now signals a `user-error' (with the recovery
  command in the message) when the server isn't running.

- slack-config.el: wrap the
  `which-key-add-keymap-based-replacements' call in
  `with-eval-after-load 'which-key'.  Matches the pattern other
  config modules use and means a slow / missing which-key load
  won't block requiring slack-config.

- ai-vterm.el: pass the inner shell-command-string through
  `shell-quote-argument' before wrapping in the tmux invocation.
  The default value with embedded double quotes was safe under the
  prior literal-single-quote wrap, but a user-customized
  `cj/ai-vterm-agent-command' containing a single quote silently
  broke the shell parse.  Two existing tests updated to tolerate
  the post-quote escape shape; new regression test asserts a
  single-quote-bearing custom command survives.

- eshell-config.el: scope the `TERM=xterm-256color' override to
  eshell-spawned processes only via an `eshell-mode' hook that
  prepends to a buffer-local `process-environment'.  The previous
  global `setenv' at config-time changed `TERM' for every
  subsequent `start-process' across the Emacs session, so any
  subprocess (not just eshell pipelines) inherited
  `xterm-256color' regardless of whether the receiver could
  interpret the escapes.

1 files changed, 19 insertions, 15 deletions

diff --git a/modules/slack-config.el b/modules/slack-config.el
index 3e9ae283..b51db444 100644
--- a/modules/slack-config.el
+++ b/modules/slack-config.el
@@ -253,21 +253,25 @@ swallows exceptions via `websocket-try-callback'."
 (define-key cj/slack-keymap (kbd "Q") #'cj/slack-close-all-buffers)
 (define-key cj/slack-keymap (kbd "S") #'cj/slack-stop)
 
-(which-key-add-keymap-based-replacements cj/slack-keymap
-  "" "slack menu"
-  "s" "start slack"
-  "c" "unread rooms"
-  "C" "select channel"
-  "d" "direct message"
-  "w" "compose message"
-  "r" "reply / thread"
-  "e" "insert emoji"
-  "!" "add reaction"
-  "@" "embed @mention"
-  "#" "embed #channel"
-  "q" "mark read & bury"
-  "Q" "close all slack"
-  "S" "disconnect")
+;; Register which-key labels lazily so this module's require doesn't
+;; depend on which-key being loaded.  Other config modules use the same
+;; pattern.
+(with-eval-after-load 'which-key
+  (which-key-add-keymap-based-replacements cj/slack-keymap
+    "" "slack menu"
+    "s" "start slack"
+    "c" "unread rooms"
+    "C" "select channel"
+    "d" "direct message"
+    "w" "compose message"
+    "r" "reply / thread"
+    "e" "insert emoji"
+    "!" "add reaction"
+    "@" "embed @mention"
+    "#" "embed #channel"
+    "q" "mark read & bury"
+    "Q" "close all slack"
+    "S" "disconnect"))
 
 ;; Send from compose buffer with C-<return>
 (with-eval-after-load 'slack-message-compose-buffer