feat: complete task editing coverage (#109)

Problem: the task editing surface had gaps — category and recurrence had
no keymaps, `:Pending edit` required knowing the task ID, tasks couldn't
be reordered with a keymap, priority was binary (0/1), and `wip`/`blocked`
states were documented but unimplemented.

Solution: fill every cell so every property is editable in every way.

- `gc`/`gr` keymaps for category select and recurrence prompt
- cursor-aware `:Pending edit` (omit ID to use task under cursor)
- `J`/`K` keymaps to reorder tasks within a category
- multi-level priorities (`max_priority` config, `g!` cycles 0→1→2→3→0)
- `+!!`/`+!!!` tokens in `:Pending edit`, `:Pending add`, `parse.body()`
- `PendingPriority2`/`PendingPriority3` highlight groups
- `gw`/`gb` keymaps toggle `wip`/`blocked` status
- `>`/`=` state chars in buffer rendering and diff parsing
- `PendingWip`/`PendingBlocked` highlight groups
- sort order: wip → pending → blocked → done
- `wip`/`blocked` filter predicates and icons

plugin/pending.lua

@@ -13,6 +13,8 @@ local function edit_field_candidates()
     'cat:',
     rk .. ':',
     '+!',
+    '+!!',
+    '+!!!',
     '-!',
     '-' .. dk,
     '-cat',
@@ -181,7 +183,7 @@ end, {
       for word in after_filter:gmatch('%S+') do
         used[word] = true
       end
-      local candidates = { 'clear', 'overdue', 'today', 'priority', 'done', 'pending' }
+      local candidates = { 'clear', 'overdue', 'today', 'priority', 'done', 'pending', 'wip', 'blocked' }
       local store = require('pending.store')
       local s = store.new(store.resolve_path())
       s:load()
@@ -280,6 +282,30 @@ vim.keymap.set('n', '<Plug>(pending-undo)', function()
   require('pending').undo_write()
 end)
 
+vim.keymap.set('n', '<Plug>(pending-category)', function()
+  require('pending').prompt_category()
+end)
+
+vim.keymap.set('n', '<Plug>(pending-recur)', function()
+  require('pending').prompt_recur()
+end)
+
+vim.keymap.set('n', '<Plug>(pending-move-down)', function()
+  require('pending').move_task('down')
+end)
+
+vim.keymap.set('n', '<Plug>(pending-move-up)', function()
+  require('pending').move_task('up')
+end)
+
+vim.keymap.set('n', '<Plug>(pending-wip)', function()
+  require('pending').toggle_status('wip')
+end)
+
+vim.keymap.set('n', '<Plug>(pending-blocked)', function()
+  require('pending').toggle_status('blocked')
+end)
+
 vim.keymap.set('n', '<Plug>(pending-filter)', function()
   vim.ui.input({ prompt = 'Filter: ' }, function(input)
     if input then