[FEATURE] Add interactive description/notes editing for marks

[alexekdahl]

Is your feature request related to a problem?

When there are many marks across a project, the auto-generated mark names and line previews aren't enough context. While the data structure supports a description field, there's no way to add, edit, or view descriptions through commands or the UI. This makes marks less useful for tracking todos, bugs, or refactoring notes across large codebases.

Describe the solution you'd like

Add full support for mark descriptions/notes with the following capabilities:

Commands:

• :MarkAdd my_mark This needs optimization - Add mark with description
• :MarkNote <mark_name> <description> - Add/edit description for existing mark
• Support description editing when creating marks interactively

UI Enhancements:

• Display descriptions below each mark in the floating window (non-minimal mode)
• Add n keymap in marks window to edit description of mark under cursor
• Add new highlight group ProjectMarksDescription for styling
• Update help text to show the new n:Note option

Integration:

• Ensure search works with descriptions (already should via mark.description)
• Preserve descriptions during mark operations (rename, move, export/import)

Describe alternatives you've considered

• Encoding notes in mark names - Limited by 50-character name limit and reduces readability

Additional context

The infrastructure already exists! The add_mark() function accepts a description parameter and stores it in the mark data structure:

local mark = {
    file = bufname,
    line = line,
    col = col,
    text = vim.fn.getline("."):sub(1, 80),
    created_at = os.time(),
    description = description,  -- Already stored!
}

This feature is mostly about exposing existing functionality through commands and UI rather than building new core features.

Implementation ideas

1. Add :MarkNote command (in init.lua):

{
    "MarkNote",
    function(args)
        local parts = vim.split(args.args, " ", { plain = true })
        if #parts >= 2 then
            local mark_name = parts[1]
            local description = table.concat(parts, " ", 2)
            local storage = require("marksman.storage")
            local marks = storage.get_marks()
            if marks[mark_name] then
                marks[mark_name].description = description
                storage.save_marks()
                notify("Description updated for: " .. mark_name, vim.log.levels.INFO)
            else
                notify("Mark not found: " .. mark_name, vim.log.levels.WARN)
            end
        end
    end,
    { nargs = "+", desc = "Add/edit mark description" },
}

2. Add n keymap for editing descriptions (in ui.lua - setup_window_keymaps):

vim.keymap.set("n", "n", function()
    local mark_info_item = get_mark_under_cursor(mark_info)
    if mark_info_item then
        vim.ui.input({
            prompt = "Description: ",
            default = mark_info_item.mark.description or "",
        }, function(description)
            if description ~= nil then
                local storage = require("marksman.storage")
                local marks = storage.get_marks()
                marks[mark_info_item.name].description = description
                storage.save_marks()
                refresh_window(search_query)
            end
        end)
    end
end, keymap_opts)

3. Display descriptions in UI (in ui.lua - create_detailed_mark_lines):

-- After file info line, add:
if mark.description and mark.description ~= "" then
    local desc_text = "    💭 " .. mark.description:sub(1, WINDOW_WIDTH - 15)
    if #mark.description > WINDOW_WIDTH - 15 then
        desc_text = desc_text .. "..."
    end
    table.insert(lines, desc_text)
    table.insert(highlights, {
        line = line_idx + 2,
        col = 4,
        end_col = -1,
        hl_group = "ProjectMarksDescription",
    })
end

4. Add highlight group (in default_config.highlights):

ProjectMarksDescription = { fg = "#7C7F93", italic = true },

5. Update help text (in create_help_line):

local help_items = {
    "<CR>/1-9:Jump",
    "d:Delete",
    "r:Rename",
    "n:Note",
    "/:Search",
    "J/K:Move",
    "C:Clear",
    "q:Close",
}

6. Modify :MarkAdd command to accept description:

-- Update MarkAdd command handler
{
    "MarkAdd",
    function(args)
        local parts = vim.split(args.args, " ", { plain = true, trimempty = true })
        local name = parts[1]
        local description = #parts > 1 and table.concat(parts, " ", 2) or nil
        local result = M.add_mark(name ~= "" and name or nil, description)
        if not result.success then
            notify(result.message, vim.log.levels.WARN)
        end
    end,
    { nargs = "?", desc = "Add a mark at current position" },
}