Problem:
TM_DIRECTORY expands to the directory's basename, losing its parent path.

Solution:
Remove the tail modifier when expanding the current file's directory.
Extend the existing known-variable test to check the full directory path.

AI-assisted

Problem: watchdirs() keeps its state in large nested callbacks in
_watch.lua, which makes its directory tracking logic harder to change.

Solution: Move the backend into its own module and store its state in a
WatchDirs instance. Split setup, event handling and cleanup into
methods. Extend the existing test to cover cancellation while a
directory stat is pending.

AI-assisted

Problem:
After edits move diagnostic ranges, counted jumps resume searching from
their original positions. This can revisit the same diagnostic and hang
the default first/last diagnostic mappings.

Solution:
Advance the search origin using the diagnostic's current logical position.
Test forward and backward counted jumps after inserting or deleting a
line, including jumps to the last or first diagnostic without wrapping.

AI-assisted

Problem: Highlight inspection is limited to a single position, and its
result types do not document the fields shared by different highlight
sources.

Solution: Accept end_row/end_col in vim.inspect_pos to inspect a range.
Keep range ends exclusive and retain the existing single-position
behavior.

Support Ex line ranges in :Inspect, including Visual selections.
Document named result types, expose shared highlight fields, and keep
the existing extmark details and buffer field for compatibility.

AI-assisted

vim.diagnostic.Opts.VirtualText has a `source` option to prefix
diagnostic messages with their source (`'if_many'` or always), but the
newer virtual_lines handler never got the same option, even though the
shared helpers it needs (diagnostic_shared.prefix_source/count_sources)
are already render-target-agnostic and used by virtual_text as-is.

Add the same `source` field to vim.diagnostic.Opts.VirtualLines and
apply it in the virtual_lines handler right after message formatting,
mirroring virtual_text's own ordering (format first, then prefix the
source onto the already-formatted message).

Problem:
- nvim_buf_call() aborts (assert) when called from an expression evaluated
  for a window in another tabpage ('foldexpr', 'statusline'), because
  `curwin` is not in `curtab`.
- After it returns, `curwin` is wrong if it switched windows.
- `vim._with{win=…, keepcwd=true}` does not undo `:lcd` if `win` is in
  another tabpage.

Solution:
- Allow `curwin` outside `curtab`, and restore if it was outside
  `curtab` at `ctx_switch()`.
- Find the target window in any tabpage when restoring its dirs.

Problem:
`nvim_set_option_value('fo', {'c','r','o'}, {operation='remove'})` does
nothing on "jcqrol": the items are joined into one `:set-=` value, which
only matches a contiguous substring. Removing map keys, e.g. {'eol','space'}
from 'listchars', never matches. `vim.opt:remove{…}` inherits this.

(Regression from f34ee3da80e8; 429338e74bf4 fixed the case where the
flags are adjacent and in order.)

Solution:
Remove each item separately.

Problem:
Handlers defer `show()` on unloaded buffers with a buffer-local BufRead
autocmd whose id is stored per-namespace:
- `noautocmd bwipeout` deletes the autocmd, so the next show/hide fails.
- Showing another buffer in the same namespace cancels the pending show.

Solution:
Handlers skip unloaded buffers. The existing global BufRead autocmd
shows cached diagnostics when the buffer loads.

perf(watch): skip directories outside include glob prefixes

Problem:
`vim.fs.find()` checks `type` against the symlink itself, so
`{ type='file', follow=true }` skips symlinked files (e.g. `:helptags`).

Solution:
With `follow=true`, a symlink has the type of its target. Thus
`type='link'` only matches broken symlinks (like `find -L -type l`).