fix: parse SSH config entries with tabs as well as spaces

resolve_ssh_alias() now extracts tokens with 'read -r', which
collapses tabs and spaces uniformly. Two bugs were at play:

1. The previous parser split on literal spaces
   (key="${line%% *}") and used '${line#Host }' to drop the
   Host directive, so configs that used tab indentation
   (e.g. '\tHostName 10.60.16.35') ended up with key being the
   whole line and never matching the case branches. Result:
   'has no HostName in ~/.ssh/config' even when one was present.

2. The script's global IFS is $'\n\t' (no space), which made
   'read' unable to split on spaces at all. Fixed by restoring
   space-aware IFS locally inside the loop.

Verified against tabbed, spaced, mixed, indented-comment and
Host\tname configs; behavior with the original space-separated
configs is unchanged.

scripts/build-and-push.sh

@@ -130,15 +130,19 @@ resolve_ssh_alias() {
   [[ -f "$config" ]] \
     || die "Cannot resolve '$alias': $config not found and value has no '@'."
 
-  local in_block=0 hostname="" user="" port="" identity="" line key value p
+  local in_block=0 hostname="" user="" port="" identity="" line first p
   local -a patterns
-  while IFS= read -r line || [[ -n "$line" ]]; do
+  # Force whitespace-aware splitting (the script's global IFS excludes spaces).
-    line="${line#"${line%%[![:space:]]*}"}"
+  local IFS=$' \t\n'
-    [[ -z "$line" || "${line:0:1}" == "#" ]] && continue
+  while read -r line || [[ -n "$line" ]]; do
-    key="${line%% *}"
+    # First whitespace-separated token (tabs and spaces collapse uniformly).
-    if [[ "$key" == "Host" ]]; then
+    read -r first _ <<< "$line"
+    [[ -z "$first" || "$first" == "#" ]] && continue
+
+    if [[ "$first" == "Host" ]]; then
       if (( in_block )); then break; fi
-      read -r -a patterns <<< "${line#Host }"
+      read -r -a patterns <<< "$line"
+      patterns=("${patterns[@]:1}")
       in_block=0
       for p in "${patterns[@]}"; do
         if [[ "$p" == "$alias" ]]; then
@@ -149,12 +153,13 @@ resolve_ssh_alias() {
       done
       continue
     fi
+
     if (( in_block )); then
-      case "$key" in
+      case "$first" in
-        HostName)     hostname="${line#* }" ;;
+        HostName)     read -r _ hostname <<< "$line" ;;
-        User)         user="${line#* }" ;;
+        User)         read -r _ user     <<< "$line" ;;
-        Port)         port="${line#* }" ;;
+        Port)         read -r _ port     <<< "$line" ;;
-        IdentityFile) identity="${line#* }" ;;
+        IdentityFile) read -r _ identity <<< "$line" ;;
       esac
     fi
   done < "$config"