fix: Improve Confluence/Jira detection precision

- Add domain-specific matching for Atlassian services
- Fix Confluence being misclassified as Jira
- Add comprehensive test coverage for notification detection
- Add example configuration file with new options
- All 13 tests now passing

Files modified:
- src/mail/notification_detector.py: Better atlassian.net handling
- tests/test_notification_detector.py: Full test suite
- mail.toml.example: Config documentation with examples

mail.toml.example

@@ -0,0 +1,82 @@
+# LUK Mail Configuration Example
+# Copy this file to ~/.config/luk/mail.toml and customize
+
+# [task]
+# # Task management backend (taskwarrior or dstask)
+# backend = "taskwarrior"
+# taskwarrior_path = "task"
+# dstask_path = "~/.local/bin/dstask"
+
+[envelope_display]
+# Sender name maximum length before truncation
+max_sender_length = 25
+
+# Date/time formatting
+date_format = "%m/%d"
+time_format = "%H:%M"
+show_date = true
+show_time = true
+
+# Group envelopes by date
+# "relative" = Today, Yesterday, This Week, etc.
+# "absolute" = December 2025, November 2025, etc.
+group_by = "relative"
+
+# Layout: 2-line or 3-line (3-line shows preview)
+lines = 2
+show_checkbox = true
+show_preview = false
+
+# NerdFont icons
+icon_unread = "\uf0e0"     # nf-fa-envelope (filled)
+icon_read = "\uf2b6"       # nf-fa-envelope_open (open)
+icon_flagged = "\uf024"    # nf-fa-flag
+icon_attachment = "\uf0c6" # nf-fa-paperclip
+
+[content_display]
+# Default view mode: "markdown" or "html"
+default_view_mode = "markdown"
+
+# URL compression settings
+compress_urls = true
+max_url_length = 50
+
+# Notification email compression
+# "summary" - Brief one-page summary
+# "detailed" - More details in structured format
+# "off" - Disable notification compression
+compress_notifications = true
+notification_compression_mode = "summary"
+
+[link_panel]
+# Close link panel after opening a link
+close_on_open = false
+
+[mail]
+# Default folder to archive messages to
+archive_folder = "Archive"
+
+[keybindings]
+# Custom keybindings (leave blank to use defaults)
+# next_message = "j"
+# prev_message = "k"
+# delete = "#"
+# archive = "e"
+# open_by_id = "o"
+# quit = "q"
+# toggle_header = "h"
+# create_task = "t"
+# reload = "%"
+# toggle_sort = "s"
+# toggle_selection = "space"
+# clear_selection = "escape"
+# scroll_page_down = "pagedown"
+# scroll_page_up = "b"
+# toggle_main_content = "w"
+# open_links = "l"
+# toggle_view_mode = "m"
+
+[theme]
+# Textual theme name
+# Available themes: monokai, dracula, gruvbox, nord, etc.
+theme_name = "monokai"