refactor(core): Require Neovim 0.12 and align Treesitter handling

[mhiro2]

Summary

• Require Neovim 0.12 as the minimum version in documentation
• Fix Treesitter parser detection for Neovim 0.12 where get_parser() returns nil instead of raising an error
• Remove pre-0.12 UTF-32 indexing compatibility code
• Modernize API usage by switching quickfix opening to nvim_cmd()
• Disable ShaDa writes in headless tests to prevent side effects

Changes

• 293e82c : refactor(core): require Neovim 0.12 and align Treesitter handling
  • Updated README and help documentation to reflect Neovim 0.12 minimum requirement
  • Fixed Treesitter parser detection to handle nil return from get_parser() instead of error handling
  • Removed UTF-32 indexing compatibility branches that are no longer needed for 0.12+
  • Modernized quickfix opening by switching from vim.cmd() to nvim_cmd()
  • Updated symbol and grep tests to validate behavior under Neovim 0.12 constraints

[github-actions]

Benchmark Results

nvim --headless -u NONE -c "lua dofile('bench/run.lua')" -c "qa!"

== bench.bench_reapply ==
---------------------------------------------------------------------------------------------
Benchmark                                        Iters    Mean (us)     Min (us)     Max (us)
---------------------------------------------------------------------------------------------
reapply_all  slots=1 wins=1                         50          2.5          0.6         20.1
reapply_all  slots=1 wins=5                         50          6.0          3.4         18.5
reapply_all  slots=1 wins=10                        50         12.0          6.1         37.1
reapply_all  slots=1 wins=20                        50         14.0         11.8         28.9
reapply_all  slots=5 wins=1                         50          1.4          0.7         12.7
reapply_all  slots=5 wins=5                         50          6.1          3.9         13.1
reapply_all  slots=5 wins=10                        50         11.9          7.0         40.5
reapply_all  slots=5 wins=20                        50         15.6         13.6         21.1
reapply_all  slots=9 wins=1                         50          1.2          0.8          2.0
reapply_all  slots=9 wins=5                         50          8.7          4.2         31.4
reapply_all  slots=9 wins=10                        50          8.1          7.9          8.5
reapply_all  slots=9 wins=20                        50         26.5         16.2         86.1
---------------------------------------------------------------------------------------------

== bench.bench_apply ==
---------------------------------------------------------------------------------------------
Benchmark                                        Iters    Mean (us)     Min (us)     Max (us)
---------------------------------------------------------------------------------------------
apply_slot_globally  wins=1                        100          4.6          3.9         23.2
apply_slot_globally  wins=5                        100         19.7         18.4         46.5
apply_slot_globally  wins=10                       100         44.3         37.3         93.2
apply_slot_globally  wins=20                       100         84.3         74.5        150.6
apply_slot_for_window  existing=0                  200          5.8          3.7         31.3
apply_slot_for_window  existing=5                  200          4.5          4.2         23.7
apply_slot_for_window  existing=9                  200          5.0          4.6         24.5
---------------------------------------------------------------------------------------------

== bench.bench_clear ==
---------------------------------------------------------------------------------------------
Benchmark                                        Iters    Mean (us)     Min (us)     Max (us)
---------------------------------------------------------------------------------------------
clear_all_globally  slots=1 wins=1                  30         65.8         47.7        131.3
clear_all_globally  slots=1 wins=5                  30        151.5        130.4        279.4
clear_all_globally  slots=1 wins=10                 30        288.2        236.7        550.0
clear_all_globally  slots=5 wins=1                  30        100.4         72.7        203.6
clear_all_globally  slots=5 wins=5                  30        277.6        234.9        516.3
clear_all_globally  slots=5 wins=10                 30        484.2        433.0        837.9
clear_all_globally  slots=9 wins=1                  30        114.0         99.3        260.1
clear_all_globally  slots=9 wins=5                  30        410.2        349.4        644.9
clear_all_globally  slots=9 wins=10                 30        745.9        659.7        990.2
---------------------------------------------------------------------------------------------

== bench.bench_set_clear ==
---------------------------------------------------------------------------------------------
Benchmark                                        Iters    Mean (us)     Min (us)     Max (us)
---------------------------------------------------------------------------------------------
set+clear cycle  wins=1                             50         31.1         13.6        282.6
set+clear cycle  wins=5                             50         50.9         37.0         86.8
set+clear cycle  wins=10                            50         72.5         66.7         94.8
---------------------------------------------------------------------------------------------

== bench.bench_jump ==---------------------------------------------------------------------------------------------
Benchmark                                        Iters    Mean (us)     Min (us)     Max (us)
---------------------------------------------------------------------------------------------
jump.next  slots=1                                 100         25.5          8.8         69.3
jump.next  slots=5                                 100       5081.8       4968.0       5477.8
jump.next  slots=9                                 100      15340.0      15133.9      16166.2
---------------------------------------------------------------------------------------------

== bench.bench_cword ==
---------------------------------------------------------------------------------------------
Benchmark                                        Iters    Mean (us)     Min (us)     Max (us)
---------------------------------------------------------------------------------------------
apply_cword_for_window                             200          2.4          2.1         29.0
---------------------------------------------------------------------------------------------

== bench.bench_symbol ==
---------------------------------------------------------------------------------------------
Benchmark                                        Iters    Mean (us)     Min (us)     Max (us)
---------------------------------------------------------------------------------------------
symbol: get_symbol (on identifier)                 200         12.0          4.1        194.7
symbol: get_symbol (on keyword)                    200         16.2          5.7         70.0
symbol: set+clear cycle (source=symbol)             50         28.1         17.1        117.2
symbol: set+clear cycle (source=cword)              50         14.9         13.0         40.4
---------------------------------------------------------------------------------------------

== SUMMARY ==
---------------------------------------------------------------------------------------------
Benchmark                                        Iters    Mean (us)     Min (us)     Max (us)
---------------------------------------------------------------------------------------------
reapply_all  slots=1 wins=1                         50          2.5          0.6         20.1
reapply_all  slots=1 wins=5                         50          6.0          3.4         18.5
reapply_all  slots=1 wins=10                        50         12.0          6.1         37.1
reapply_all  slots=1 wins=20                        50         14.0         11.8         28.9
reapply_all  slots=5 wins=1                         50          1.4          0.7         12.7
reapply_all  slots=5 wins=5                         50          6.1          3.9         13.1
reapply_all  slots=5 wins=10                        50         11.9          7.0         40.5
reapply_all  slots=5 wins=20                        50         15.6         13.6         21.1
reapply_all  slots=9 wins=1                         50          1.2          0.8          2.0
reapply_all  slots=9 wins=5                         50          8.7          4.2         31.4
reapply_all  slots=9 wins=10                        50          8.1          7.9          8.5
reapply_all  slots=9 wins=20                        50         26.5         16.2         86.1
apply_slot_globally  wins=1                        100          4.6          3.9         23.2
apply_slot_globally  wins=5                        100         19.7         18.4         46.5
apply_slot_globally  wins=10                       100         44.3         37.3         93.2
apply_slot_globally  wins=20                       100         84.3         74.5        150.6
apply_slot_for_window  existing=0                  200          5.8          3.7         31.3
apply_slot_for_window  existing=5                  200          4.5          4.2         23.7
apply_slot_for_window  existing=9                  200          5.0          4.6         24.5
clear_all_globally  slots=1 wins=1                  30         65.8         47.7        131.3
clear_all_globally  slots=1 wins=5                  30        151.5        130.4        279.4
clear_all_globally  slots=1 wins=10                 30        288.2        236.7        550.0
clear_all_globally  slots=5 wins=1                  30        100.4         72.7        203.6
clear_all_globally  slots=5 wins=5                  30        277.6        234.9        516.3
clear_all_globally  slots=5 wins=10                 30        484.2        433.0        837.9
clear_all_globally  slots=9 wins=1                  30        114.0         99.3        260.1
clear_all_globally  slots=9 wins=5                  30        410.2        349.4        644.9
clear_all_globally  slots=9 wins=10                 30        745.9        659.7        990.2
set+clear cycle  wins=1                             50         31.1         13.6        282.6
set+clear cycle  wins=5                             50         50.9         37.0         86.8
set+clear cycle  wins=10                            50         72.5         66.7         94.8
jump.next  slots=1                                 100         25.5          8.8         69.3
jump.next  slots=5                                 100       5081.8       4968.0       5477.8
jump.next  slots=9                                 100      15340.0      15133.9      16166.2
apply_cword_for_window                             200          2.4          2.1         29.0
symbol: get_symbol (on identifier)                 200         12.0          4.1        194.7
symbol: get_symbol (on keyword)                    200         16.2          5.7         70.0
symbol: set+clear cycle (source=symbol)             50         28.1         17.1        117.2
symbol: set+clear cycle (source=cword)              50         14.9         13.0         40.4
---------------------------------------------------------------------------------------------