0.6.5: HTML Telegram digest + fix silently-empty beet sections + watermark-art resilience

The daily digest is now formatted with Telegram HTML: bold section headers
with <pre>-aligned columns, colored circle emoji as status dots, a branded
header line, and a top blockquote callout (all clear vs N issues). All free
text is &/</> escaped so a stray angle bracket in a log snippet can't break
the parse and swallow the whole message. notify-telegram.sh gains an --html
flag (parse_mode=HTML) used by the digest send; plain-text callers are
unchanged. Truncation is now tag-safe in HTML mode: cut on a line boundary,
re-close an open <pre>, and use an escaped marker -- the old literal
"...<truncated>" tail would itself have 400'd the send.

Two real bugs surfaced while testing:

- pipeline-status.sh pins its own PATH, which lacked /opt/venv/bin where
  beet lives, so every beet probe ("added today", "Library by format", the
  mp3-now count) has been silently empty behind 2>/dev/null since the cron
  migration. PATH now includes the venv; both sections show real numbers.

- strip-watermark-art.py aborted its entire weekly run when metaflac stalled
  on ONE file (seen today: a healthy 190KB cover took >15s under disk
  contention, TimeoutExpired killed the job). Per-file timeout is now 60s
  and a timeout skips that file with a warning instead of failing the run.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

pipeline/lib/notify-telegram.sh

@@ -5,14 +5,29 @@
 # Usage:
 #   echo "single line message" | notify-telegram.sh
 #   notify-telegram.sh "single line message"
-#   notify-telegram.sh < ${ALEMBIC_CONFIG_DIR:-/config}/logs/STATUS.log
+#   notify-telegram.sh --html < ${ALEMBIC_CONFIG_DIR:-/config}/logs/STATUS.log
 #
-# Telegram messages are capped at 4096 chars. Anything longer is truncated
-# with a "...<truncated>" tail. Returns exit 0 on send-OK, non-zero otherwise.
+# --html sends with parse_mode=HTML for messages authored as Telegram-HTML
+# (pipeline-status.sh's digest: <b>/<i>/<code>/<pre>/<blockquote>). The
+# CALLER is responsible for escaping &, <, > in any free text; this script
+# only guarantees the truncation below can't cut a tag in half. Without the
+# flag, messages go as plain text exactly as before.
+#
+# Telegram messages are capped at 4096 chars. Anything longer is truncated;
+# in HTML mode the cut lands on a line boundary and re-closes an open <pre>
+# so the truncated message still parses (a mid-tag cut, or a bare "<" in the
+# tail marker, makes the Bot API reject the ENTIRE message with a 400).
+# Returns exit 0 on send-OK, non-zero otherwise.
 
 set -euo pipefail
 PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
 
+PARSE_MODE=""
+if [[ "${1:-}" == "--html" ]]; then
+  PARSE_MODE="HTML"
+  shift
+fi
+
 CONFIG="${ALEMBIC_CONFIG_DIR:-/config}/pipeline/telegram/notify.env"
 if [[ ! -f "$CONFIG" ]]; then
   echo "[notify-telegram] no config at $CONFIG" >&2
@@ -30,24 +45,37 @@ else
   MSG=$(cat)
 fi
 
-# Telegram caps at 4096 chars (UTF-8 codepoints). Trim conservatively at 3900.
-# Use python for proper UTF-8 length handling.
+# Telegram caps at 4096 chars. Trim conservatively at 3900. Use python for
+# proper UTF-8 length handling. Plain mode appends a literal marker; HTML
+# mode cuts at the last newline inside the budget (our tags never span
+# lines except <pre> blocks) and re-closes an unbalanced <pre>.
 MSG=$(python3 -c "
 import sys
 s = sys.argv[1]
+html = sys.argv[2] == 'HTML'
 if len(s) > 3900:
-    s = s[:3900] + '\n...<truncated>'
+    s = s[:3900]
+    if html:
+        cut = s.rfind('\n')
+        if cut > 0:
+            s = s[:cut]
+        if s.count('<pre>') > s.count('</pre>'):
+            s += '</pre>'
+        s += '\n<i>… truncated</i>'
+    else:
+        s += '\n...(truncated)'
 print(s, end='')
-" "$MSG")
+" "$MSG" "${PARSE_MODE:-plain}")
 
-# Send via Bot API. Disable web-page preview and use plain text (no parse_mode)
-# so log content with special chars doesn't get interpreted as Markdown.
+# Send via Bot API. Preview disabled; parse_mode only when requested so log
+# content with special chars can't be misread as markup in plain sends.
 # `|| true`: a curl timeout/network error must fall through to the explicit
 # ok-check below (which reports "send failed" and exits 2), not abort here.
 resp=$(curl -s --max-time 15 -X POST \
   "https://api.telegram.org/bot${TG_BOT_TOKEN}/sendMessage" \
   --data-urlencode "chat_id=${TG_CHAT_ID}" \
   --data-urlencode "text=${MSG}" \
+  ${PARSE_MODE:+--data-urlencode "parse_mode=${PARSE_MODE}"} \
   --data-urlencode "disable_web_page_preview=true" || true)
 
 ok=$(echo "$resp" | python3 -c "import sys,json;print(json.load(sys.stdin).get('ok',False))" 2>/dev/null || echo False)