feat(adapters): Go syntax-aware and PowerShell native-location adapters

[joncrangle]

Closes #13.

Why

Go and PowerShell/pwsh still use line-oriented wrapper instrumentation with synthetic per-line tracking, wrapper-shifted diagnostics, and magic offset corrections. Migrate both to the adapter/event pipeline using the strongest source-location mechanism available per runtime (syntax-aware for Go, native invocation metadata for PowerShell), keeping dosbatch/CMD on the compatibility adapter.

What

• Go: Tree-sitter targeted instrumentation of fmt/log Print/Printf/Println (callee-only rewrites, line-preserving, multiline-safe); locations via runtime.Caller; native compiler/panic diagnostics. No Tree-sitter parser on the system? An embedded comment/string-aware scanner produces byte-identical rewrites (equivalence-tested) — no new hard requirement, no legacy wrapper on any path.
• PowerShell/pwsh: one adapter for pwsh + Windows PowerShell; output proxies using Get-PSCallStack line/column with user-file attribution; stream-mapped framed events (output/host to stdout, warning to warning, error to error); same-scope appended resilience trap with native InvocationInfo locations; native stderr parsing for throw/command-not-found/parse errors.
• Shared utils.make_adapter_tmpdir / utils.is_user_file; runtimes wired to the new adapters; transitional wrapper tests removed/retargeted.
• CI installs the Go Tree-sitter parser as a test-only dependency (nvim-treesitter master pin + MSVC setup on Windows) so the primary path is exercised; README documents the Tree-sitter benefit.

Verification

• Tests
• Manual Check

Full suite: 155 cases, 0 fails (local, incl. pwsh + Windows PowerShell e2e, TS/lexer equivalence, forced-scanner run). Go log output renders as stdout, not error diagnostics. Neovim 0.11 floor kept: verified neither 0.11 nor 0.12 ships a go parser, so the floor costs nothing with the scanner fallback.