feat(cli): add config path command

[ChrisJr404]

What?

Adds a matcha config path subcommand that prints the resolved config.json location and exits, without opening an editor.

Why?

Closes #1516. There's currently no quick way to find where Matcha stores its config, you either open it in $EDITOR or guess the path. Printing it is useful in scripts and for anyone who just wants the location.

The path comes from a small exported config.GetConfigFile helper so it resolves the same way the rest of the app does. Added tests for the resolver and for the wired command, and updated the README and CLI docs.

[floatpanebot]

Hi @ChrisJr404! Please fix the following issues with your PR:

• Title: Is too long (41 characters). The PR title must be strictly under 40 characters.

[floatpanebot]

Benchmark report — no significant change

Metrics worse: 0 · better: 0 (threshold: ±3%).

benchstat output

goos: linux
goarch: amd64
pkg: github.com/floatpane/matcha/backend
cpu: AMD EPYC 7763 64-Core Processor                
                           │    old.txt    │                new.txt                │
                           │    sec/op     │    sec/op      vs base                │
ParseSearchQuery_Simple-4    3.307µ ± 276%    2.472µ ± 24%         ~ (p=0.310 n=6)
ParseSearchQuery_Complex-4   8.376µ ±  42%    7.689µ ± 32%         ~ (p=0.240 n=6)
TokenizeSearchQuery-4        4.013µ ±  19%   12.230µ ± 51%  +204.79% (p=0.002 n=6)
geomean                      4.808µ           6.148µ         +27.88%

                           │  old.txt   │              new.txt               │
                           │    B/op    │    B/op     vs base                │
ParseSearchQuery_Simple-4    26.00 ± 0%   26.00 ± 0%       ~ (p=1.000 n=6) ¹
ParseSearchQuery_Complex-4   762.0 ± 0%   762.0 ± 0%       ~ (p=1.000 n=6) ¹
TokenizeSearchQuery-4        176.0 ± 0%   176.0 ± 0%       ~ (p=1.000 n=6) ¹
geomean                      151.6        151.6       +0.00%
¹ all samples are equal

                           │  old.txt   │              new.txt               │
                           │ allocs/op  │ allocs/op   vs base                │
ParseSearchQuery_Simple-4    2.000 ± 0%   2.000 ± 0%       ~ (p=1.000 n=6) ¹
ParseSearchQuery_Complex-4   23.00 ± 0%   23.00 ± 0%       ~ (p=1.000 n=6) ¹
TokenizeSearchQuery-4        9.000 ± 0%   9.000 ± 0%       ~ (p=1.000 n=6) ¹
geomean                      7.453        7.453       +0.00%
¹ all samples are equal

pkg: github.com/floatpane/matcha/tui
                    │   old.txt    │               new.txt               │
                    │    sec/op    │    sec/op      vs base              │
LogPanelView-4        155.4µ ± 14%    169.3µ ±  9%       ~ (p=0.240 n=6)
SearchOverlayView-4   172.3µ ± 12%    169.5µ ± 14%       ~ (p=0.937 n=6)
InboxConstruction-4   984.1µ ± 16%   1014.3µ ± 13%       ~ (p=0.485 n=6)
geomean               297.6µ          307.6µ        +3.39%

                    │    old.txt     │               new.txt                │
                    │      B/op      │     B/op       vs base               │
LogPanelView-4        21.79Ki ± 105%   44.67Ki ± 51%        ~ (p=0.567 n=6)
SearchOverlayView-4   56.14Ki ±   0%   44.69Ki ± 26%        ~ (p=0.582 n=6)
InboxConstruction-4   874.3Ki ±   0%   874.3Ki ±  0%        ~ (p=0.818 n=6)
geomean               102.3Ki          120.4Ki        +17.74%

                    │   old.txt   │              new.txt              │
                    │  allocs/op  │  allocs/op   vs base              │
LogPanelView-4         712.0 ± 0%    714.0 ± 0%       ~ (p=0.567 n=6)
SearchOverlayView-4    926.0 ± 0%    925.0 ± 0%       ~ (p=0.121 n=6)
InboxConstruction-4   3.478k ± 0%   3.478k ± 0%       ~ (p=0.827 n=6)
geomean               1.319k        1.319k       +0.05%

_{auto-generated by benchmarks.yml}

[floatpanebot]

Hi @ChrisJr404! Please fix the following issues with your PR:

• Title: Is too long (41 characters). The PR title must be strictly under 40 characters.

[ChrisJr404]

Trimmed the title under 40 chars. Also pushed a fix for the Windows build: TestGetConfigFile only set HOME, but os.UserHomeDir() reads USERPROFILE on Windows so the temp override was ignored and it resolved to the real profile dir. Now sets both, same as the cache tests already do.

Formatting issues have been resolved. Thank you!