feat: rewrite gh-commit in Go with local Ollama backend

Replaces the Python/Crush/DuckDB implementation with a CGO-free Go binary:
cobra CLI, modernc.org/sqlite storage, huh/lipgloss UI, and speed-tuned raw
/api/generate calls (think:false, keep_alive, capped num_predict) against a
local qwen3.5:2b. Ships as a gh extension via cli/gh-extension-precompile.

internal/ai/prompts.go

@@ -0,0 +1,84 @@
+package ai
+
+import (
+	"encoding/json"
+	"strings"
+)
+
+// Prompt text is ported unchanged from the Python tool, plus one
+// "Do not think" line per prompt as cheap insurance on small models.
+
+const commitPrompt = `You are an expert conventional commit message writer.
+Use one of these commit types: feat, fix, docs, style, refactor, breaking, test, perf, build, ci, chore, init.
+Determine a precise commit message from the provided diff and scope.
+The commit message must follow this format: <type>(<scope>): <description>
+Examples:
+- fix(core): resolve consensus timeout during high load
+- feat(did): add WebAuthn biometric authentication support
+- refactor(hway): extract Redis connection pooling to shared utility
+- init(browser): setup client package for web API-specific logic
+- perf(vault): optimize IPFS chunk size for large file uploads
+- ci(actions): update GitHub Actions pipeline for parallel module testing
+- docs(dwn): clarify data retention policies in API reference
+- test(svc): add integration tests for domain verification flow
+- breaking(ui): rename Button prop 'type' to 'variant'
+- refactor(sdk): migrate off wallet implementation in favor of @sonr.io/enclave
+- feat(react): create Enclave stateful hooks
+Never explain anything. Return only the commit message.
+Do not think. Answer immediately.
+
+{scope_hint}### Git Diff
+{diff}
+`
+
+const scopeInstructions = `You are a repository scope identifier for Conventional Commits.
+You receive a repository file tree, one repo-relative path per line.
+Map logical project areas to the repo-relative path prefixes (directories or files) they cover.
+Scope names must read well in Conventional Commits, e.g. core, api, ui, cli, docs, tests, ci, config, scripts, deps.
+Each scope maps to a JSON array of repo-relative path prefixes.
+Group related paths together and cover the meaningful source areas.
+Never create scopes for generated, vendored, or build-output paths.
+If existing scopes are provided, keep the ones that still apply, drop scopes whose paths no longer exist, and add scopes for new areas.
+Never explain anything or print your thoughts. Never include Markdown code blocks.
+Only return a single JSON object of the form {"scope": ["path", ...], ...}.
+Do not think. Answer immediately.
+`
+
+const scopePromptNew = scopeInstructions + `
+Repository file tree (one repo-relative path per line):
+
+{filetree}
+`
+
+const scopePromptUpdate = scopeInstructions + `
+Existing scopes (JSON):
+{existing}
+
+The repository structure may have changed (e.g. its .gitignore was edited).
+Updated repository file tree (one repo-relative path per line):
+
+{filetree}
+`
+
+// buildCommitPrompt fills the commit prompt with an optional scope hint and
+// the (already filtered) diff.
+func buildCommitPrompt(filteredDiff, scope string) string {
+	hint := ""
+	if scope != "" {
+		hint = "Use this scope: " + scope + "\n"
+	}
+	return strings.NewReplacer("{scope_hint}", hint, "{diff}", filteredDiff).Replace(commitPrompt)
+}
+
+// buildScopePrompt fills the scope prompt; existing may be nil for first-time
+// generation.
+func buildScopePrompt(filetree string, existing map[string][]string) string {
+	if len(existing) == 0 {
+		return strings.Replace(scopePromptNew, "{filetree}", filetree, 1)
+	}
+	blob, _ := json.MarshalIndent(existing, "", "  ")
+	return strings.NewReplacer(
+		"{existing}", string(blob),
+		"{filetree}", filetree,
+	).Replace(scopePromptUpdate)
+}