fix(mcp): match fidelity globs with path.Match, not filepath.Match

[tiendungdev]

Problem

matchFidelityGlob normalizes both the pattern and the path to forward slashes, then matches with filepath.Match — whose separator is the platform's. On Windows / is an ordinary character to that matcher, so a single * crosses it:

matchFidelityGlob("internal/*.go", "internal/sub/x.go")
  linux/macos -> false
  windows     -> true      <- TestMatchFidelityGlob, fidelity_globs_test.go:61

The file's own doc-comment states the assumption this breaks:

explicit ** support so the documented internal/** / **/*.go forms work as written (Go's filepath.Match never crosses /)

That is true on POSIX, which is exactly why the linux/macos matrix has never been able to see it.

fidelity_globs is a public tool parameter on read_file and get_editing_context, so on Windows a documented internal/*.go rule silently applied its fidelity to the entire subtree beneath internal/.

Change

path.Match / path.Base in matchSegmentGlob. Everything around it already works in slash space — ToSlash on entry, Split(rel, "/"), the ** prefix/suffix handling — so those are the primitives that space calls for. On POSIX they are identical to the filepath versions, since the separator already is /.

Verification

• TestMatchFidelityGlob red → green on windows/amd64, go1.26.6.
• Whole internal/mcp package, failing test names diffed against main (c982cf52): newly-broken set empty.

One result I am not claiming

The full-package run came back 27 → 25, but only one of those is mine. TestNotesManager_SaveQueryDelete also flipped to green in that run — and it is not fixed by this change: run in isolation on this very branch it fails 3 times out of 3. It is a pre-existing order/parallelism-dependent flake that happened to pass in that particular full-package run, so the honest attributable delta is one test, not two.

No cross-platform test is possible

path.Match and filepath.Match are the same function on POSIX, so an assertion here passes on linux/macos before and after. The guard belongs in the windows Test native-separator store path comparisons step, whose package list already carries internal/mcp — but I have left ci.yml untouched here because #646 is open against that exact -run line and I would rather not hand you a conflict. Happy to add FidelityGlob to it in a follow-up once #646 lands, or fold it into #646 if you prefer that order.

Related, deliberately not included

internal/mcp/tools_generate_skill.go has the mirror-image inconsistency: matchPathPattern there receives a native rel (filepath.Rel at :134), so its filepath.Match is correct, while :540 tests strings.HasPrefix(rel, prefix+"/") against that same native path. Different bug, different fix, own change.

Branched from main at c982cf52. Windows 11, go1.26.6.

[zzet]

@tiendungdev IMO, it will be more beneficial to have a full test suite run for Windows as well as for Linux/MacOS - which is added in the #652 PR