project: add versioned release workflow and squirrel version

[mbertschler]

Summary

Gives squirrel a release/packaging story: semver tags become the source of truth for the tool version, that version is stamped into the binary at build time, and a tag push produces a GitHub Release with cross-platform binaries. Closes the gap where the only install path was go install ...@latest from source and the binary could not report what it was (0.0.0-dev placeholder).

Changes

• Build-time version injection (cmd/squirrel/version.go): replaces the hardcoded agentVersion = "0.0.0-dev" const in agent.go with package-level version / commit / date vars, injected via -ldflags -X main.*. The same version string feeds the agent's GET /v1/health response and its startup log line. A plain go build / go install keeps the 0.0.0-dev placeholder, so a source build stays distinguishable from a tagged release.
• squirrel version subcommand (own file, per the one-cobra-command-per-file convention): prints version, commit, build date, and the Go toolchain / target platform.
• .goreleaser.yaml: cross-compiles the CGO-free CLI (modernc.org/sqlite is pure Go) for linux/darwin/windows × amd64/arm64, injects the ldflags, and produces tar.gz (zip on Windows) archives plus a checksums.txt. cmd/squirrel-desktop (Wails + CGO + native WebKitGTK) is deliberately out of scope.
• .github/workflows/release.yml: tag-triggered (v*.*.*) workflow that runs GoReleaser, modeled on the existing ci.yml style.
• README.md §Install: documents the prebuilt-binary path alongside go install.

No DB schema change — the tool's release version is separate from SchemaVersion, which is untouched.

Testing

• go vet ./... — clean
• go test ./... — all pass (added TestVersionCommand; existing /v1/health test still passes)
• golangci-lint run (v2.12.2) — 0 issues
• Verified -ldflags -X injection: a build with main.version=v1.2.3 reports squirrel v1.2.3 via squirrel version
• Verified CGO-free cross-compilation for linux/arm64, darwin/arm64, windows/amd64
• goreleaser check (v2.12.5) validates .goreleaser.yaml

Closes #151

🤖 Generated with Claude Code

https://claude.ai/code/session_014Skm2Qm6wWUB7dD4CpPTz7

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Generated by Claude Code

[Copilot]

Pull request overview

Adds a first-class release/versioning story for squirrel: semver tags drive GitHub Releases with cross-platform CLI binaries, and the built binary now reports its stamped version (both via squirrel version and the agent’s /v1/health).

Changes:

• Introduces build-time-injected build metadata (version/commit/date) and a new squirrel version subcommand (with tests).
• Wires the injected version string into the agent’s startup log and /v1/health response.
• Adds GoReleaser configuration + a tag-triggered GitHub Actions release workflow, and updates install docs to include prebuilt binaries.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
README.md	Documents installing from GitHub Releases alongside go install, and notes version reporting.
cmd/squirrel/version.go	Adds build metadata variables and implements squirrel version output formatting.
cmd/squirrel/version_test.go	Adds coverage for the version command output.
cmd/squirrel/root.go	Registers the new version subcommand.
cmd/squirrel/agent.go	Replaces the old hardcoded agent version with the injected build version.
.goreleaser.yaml	Defines cross-platform CLI builds/archives/checksums and ldflags injection.
.github/workflows/release.yml	Adds tag-triggered workflow to run GoReleaser and publish a GitHub Release.

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